A control method for improving dynamic response of switch power is based on a control system comprising a sampling module, a dynamic control module, an error calculation module, a PID module, a mode control module, and a PWM module, and the control system is connected to the controlled switch power to form a closed loop.

The sampling module comprises a sampling circuit and a sampling calculation module, the sampling circuit outputs a partial voltage through the switch power to obtain the information of the output voltage, and the sampling calculation module calculates a signal Vo of the size of the output voltage according to the result of the sampling circuit.

The dynamic control module comprises a voltage monitoring module and a slope calculation module; the voltage monitoring module receives a sampling result Vo outputted by the sampling module and determines whether to adopt a dynamic mode according to the relationship between Vo and a set maximum voltage Vomax, a set minimum voltage Vomin, and a reference voltage Vref respectively, wherein Vomin<Vref<Vomax; the dynamic mode means that when the output voltage Vo changes greatly, the output voltage Vo is rapidly restored to a stable voltage by inputting large power or small power, and the dynamic mode comprises a constant-frequency light-to-heavy load LTH mode and a constant-frequency heavy-to-light load HTL mode.