What is claimed is:1. A subscriber identification module (SIM) card sharing method, comprising:in response to a first device's requirement for obtaining cellular mobile communication, sending, by the first device, share request information to a second device through an interactive channel, wherein the interactive channel is established between the first device and the second device through a preset connection manner;receiving, by the first device, SIM card information that is returned by the second device based on the share request information; andestablishing, by the first device, a cellular mobile communication connection with a base station according to the SIM card information returned by the second device,wherein establishing the cellular mobile communication connection with the base station according to the SIM card information returned by the second device comprises:sending a network access request to the base station according to the SIM card information;receiving an authentication request that is returned by the base station based on the network access request;generating an authentication response based on the SIM card information and the authentication request; andsending the authentication response to the base station, wherein the authentication response is configured to allow the first device to establish a cellular mobile communication connection with the base station in response to the authentication response passing an authentication verification.2. The method according to claim 1, wherein the first device's requirement for obtaining cellular mobile communication comprises at least one of following:the first device enters a Share-SIM client mode;the first device receives a sharing command for sharing a SIM card; orthe first device receives a command to perform cellular mobile communication when no available SIM card exists in the first device.3. The method according to claim 2, wherein a situation that no available SIM card exists in the first device comprises at least one of following scenarios:no SIM card is installed in the first device;the SIM card installed in the first device is in a deactivated state;the SIM card installed in the first device breaks down; orthe SIM card installed in the first device is not registered.4. The method according to claim 2, further comprising:in response to the first device entering the Share-SIM client mode, determining whether an available SIM card exists in the first device; andin response to determining that an available SIM card exists in the first device, deactivating the available SIM card in the first device.5. The method according to claim 4, further comprising:activating the SIM card in a deactivated state in the first device in response to the first device exiting the client mode.6. The method according to claim 1, wherein the preset connection comprises at least one of following:a Bluetooth connection;a Wi-Fi direct connection;a network connection in a same Wi-Fi LAN; ora device-to-device (D2D) connection.7. A subscriber identification module (SIM) card sharing method, comprising:receiving, by a second device, share request information sent, through an interactive channel, by a first device, wherein the share request information is configured to request SIM card information of the second device, and the interactive channel is established between the first device and the second device through a preset connection manner; andreturning, by the second device, the SIM card information to the first device through the interactive channel in response to the share request information, wherein the SIM card information is at least configured to allow the first device to establish a cellular mobile communication connection with a base station,wherein the SIM card information is configured by the first device to send a network access request to a network, and the method further comprises:receiving an authentication request through the interactive channel, wherein the authentication request is generated by the base station based on the network access request and transferred by the first device; andsending, by the second device, the SIM card information to the first device, wherein the SIM card information is required by the first device to generate an authentication response, and the first device generates the authentication response based on the SIM card information and the authentication request,wherein the authentication response is configured to allow the first device to perform an authentication verification of the cellular mobile communication connection with the base station.8. The method according to claim 7, further comprising:determining whether the second device enters a Share-SIM server mode; andwherein returning the SIM card information to the first device through the interactive channel in response to the share request information further comprises:in response to the second device entering the server mode, returning, through the interactive channel, the SIM card information to the first device based on the share request information.9. The method according to claim 8, further comprising:deactivating the SIM card of the second device after the second device enters the server mode; andactivating a deactivated SIM card of the second device after the second device exits the server mode.10. A subscriber identification module (SIM) card sharing device, applied to a first device and comprising: a processor and a memory, wherein the memory is configured to store a computer program that, when executed by the processor, causes the processor to:in response to the first device's requirement for obtaining cellular mobile communication, send share request information to a second device through an interactive channel, wherein the interactive channel is established between the first device and the second device through a preset connection manner;receive SIM card information that is returned by the second device based on the share request information; andestablish a cellular mobile communication connection with a base station according to the SIM card information returned by the second device;wherein the processor is further configured to:send a network access request to the base station according to the SIM card information;receive an authentication request that is returned by the base station based on the network access request;generate the authentication response based on the card information and the authentication request; andsend the authentication response to the base station, wherein the authentication response is configured to allow the first device to establish a cellular mobile communication connection with the base station in response to the authentication response passing an authentication verification.11. The SIM card sharing device according to claim 10, wherein the first device's requirements for obtaining cellular mobile communication comprise at least one of following:the first device enters a Share-SIM client mode;the first device receives a sharing command for sharing a SIM card; orthe first device receives a command to perform cellular mobile communication when no available SIM card is in the first device.12. The SIM card sharing device according to claim 11, wherein a situation that no available SIM card exists in the first device comprises at least one of following scenarios:no SIM card is installed in the first device;the SIM card installed in the first device is in a deactivated state;the SIM card installed in the first device breaks down; orthe SIM card installed in the first device is not registered.13. The SIM card sharing device according to claim 11, the processor is further configured to:determine whether an available SIM card exists in the first device in response to the first device entering the Share-SIM client mode; andin response to determining that an available SIM card exists in the first device, deactivate the available SIM card in the first device.14. The SIM card sharing device according to claim 13, the processor is further configured to:activate the SIM card in a deactivated state in the first device in response to the first device exiting the client mode.