An LED lamp control system, comprising: a power supply configured to convert a utility power into a DC constant voltage output and having a first power supply output terminal and a second power supply output terminal, a MOS transistor electrically connected to one of the first and second power supply output terminals, a signal encoding module for controlling the on and off of the MOS transistor, a control signal input module electrically connected to the signal encoding module, a MOS transistor control module electrically connected to the MOS transistor, an LED lamp electrically connected to the power supply and having a first lamp input end and a second lamp input end, a filter capacitor electrically connected to the first lamp input end and the second lamp input end, a signal decoding module electrically connected to the LED lamp, wherein the signal decoding module is configured to convert a PWM signal loaded on the power supply output terminal (101, 102) connected to the MOS transistor into a dimming signal, a DC/DC converter controlled by the signal decoding module, wherein the control signal input module is configured to output a control signal, and the DC/DC converter is configured to control the output parameters of the LED lamp according to the dimming signal; characterized by a signal change judging module electrically connected to the control signal input module; wherein the signal change judging module is configured to determine whether the currently outputted control signal of the control signal input module has changed with respect to the control signal outputted previously by the control signal input module, the signal encoding module is configured to convert the current control signal outputted by the control signal input module into a modulated signal when it is determined by the signal change judging module that the current control signal outputted by the control signal input module is different from the previous control signal and output the modulated signal to control the on and off of the MOS transistor to load the PWM signal onto the power supply output terminal (101, 102) connected to the MOS transistor, and the MOS transistor control module is configured to turn on the MOS transistor when it is determined by the signal change judging module that there is no change between the previous control signal and the current control signal. a power supply configured to convert a utility power into a DC constant voltage output and having a first power supply output terminal and a second power supply output terminal, a MOS transistor electrically connected to one of the first and second power supply output terminals, a signal encoding module for controlling the on and off of the MOS transistor, a control signal input module electrically connected to the signal encoding module, a MOS transistor control module electrically connected to the MOS transistor, an LED lamp electrically connected to the power supply and having a first lamp input end and a second lamp input end, a filter capacitor electrically connected to the first lamp input end and the second lamp input end, a signal decoding module electrically connected to the LED lamp, wherein the signal decoding module is configured to convert a PWM signal loaded on the power supply output terminal (101, 102) connected to the MOS transistor into a dimming signal, a DC/DC converter controlled by the signal decoding module, wherein the control signal input module is configured to output a control signal, and the DC/DC converter is configured to control the output parameters of the LED lamp according to the dimming signal; characterized by a signal change judging module electrically connected to the control signal input module; wherein the signal change judging module is configured to determine whether the currently outputted control signal of the control signal input module has changed with respect to the control signal outputted previously by the control signal input module, the signal encoding module is configured to convert the current control signal outputted by the control signal input module into a modulated signal when it is determined by the signal change judging module that the current control signal outputted by the control signal input module is different from the previous control signal and output the modulated signal to control the on and off of the MOS transistor to load the PWM signal onto the power supply output terminal (101, 102) connected to the MOS transistor, and the MOS transistor control module is configured to turn on the MOS transistor when it is determined by the signal change judging module that there is no change between the previous control signal and the current control signal.