The system for rejoining a network after network disconnection of a mobile terminal according to one or more embodiments of the present disclosure can enable the mobile terminal to rejoin a network quickly once the mobile terminal disconnects from a network, by adding the temporary broadcast frame of the nearby gateways. When the gateway does not receive information of an intelligent mobile terminal within the coverage thereof at a predetermined moment, the gateway feeds back a network-disconnected state and a network-disconnection time of the intelligent mobile terminal to the server. Then the server sends an instruction to the nearby gateways of the gateway according to the location of the gateway, instructing the nearby gateways to send a temporary broadcast frame in a latest idle time slot, so that the mobile terminal can detect the broadcast frame in a relatively short time and register to the gateway to join a network, thus enabling the mobile terminal to rejoin a network quickly. The system for rejoining a network after network disconnection of a mobile terminal according to one or more embodiments of the present disclosure can realize the purpose of rejoining a network quickly by adding the temporary broadcast frame of the nearby gateways according to the location of the gateway to which the mobile terminal belongs before network disconnection. The system for rejoining a network after network disconnection of a mobile terminal according to one or more embodiments of the present disclosure can greatly shorten the time for the mobile terminal disconnected from the network to detect a gateway broadcast, thus realizing the purpose of enabling the mobile terminal to rejoin a network quickly, and achieving the effects of reducing the power consumption of the mobile terminal and improving the response time of the mobile terminal.