An automatic sensing system for LED lighting, comprising: at least one LED lamp, each of the at least one LED lamp comprising at least three operation modes, the three operation modes comprising a closing mode, a low light mode, and a fill light mode; at least one sensing control device electrically connected to the at least one LED lamp and configured for controlling the at least one LED lamp to work in one of the three operation modes, the sensing control device comprising an illumination detecting module, a pyroelectric sensing module, a signal processing module, and a lamp control module, the illumination detecting module being configured for detecting brightness of a current environment, the pyroelectric sensing module being configured for sensing infrared rays radiated by human body in the current environment, the signal processing module being configured for outputting a control signal, the lamp control module being configured for receiving the control signal and controlling the LED lamps to work in one of the three operation modes according to the control signal; wherein the illumination detecting module provides a data signal based on the brightness level of the current environment, the brightness level comprises three stages, the brightness of the first stage is greater than 200 lumens, the brightness of the second stage is less than 200 lumens and greater than 1 lumen, and the brightness level of the third stage is less than 1 lumen, in the first stage the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the closing mode such that the at least one LED stops working, in the second stage, the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the fill light mode, in the third stage, the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the low light mode, characterized in that the pyroelectric sensing module is configured to start to sense only when the signal data is according to the low light mode or the fill light mode. at least one LED lamp, each of the at least one LED lamp comprising at least three operation modes, the three operation modes comprising a closing mode, a low light mode, and a fill light mode; at least one sensing control device electrically connected to the at least one LED lamp and configured for controlling the at least one LED lamp to work in one of the three operation modes, the sensing control device comprising an illumination detecting module, a pyroelectric sensing module, a signal processing module, and a lamp control module, the illumination detecting module being configured for detecting brightness of a current environment, the pyroelectric sensing module being configured for sensing infrared rays radiated by human body in the current environment, the signal processing module being configured for outputting a control signal, the lamp control module being configured for receiving the control signal and controlling the LED lamps to work in one of the three operation modes according to the control signal; wherein the illumination detecting module provides a data signal based on the brightness level of the current environment, the brightness level comprises three stages, the brightness of the first stage is greater than 200 lumens, the brightness of the second stage is less than 200 lumens and greater than 1 lumen, and the brightness level of the third stage is less than 1 lumen, in the first stage the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the closing mode such that the at least one LED stops working, in the second stage, the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the fill light mode, in the third stage, the illumination detecting module outputs said data signal so that the signal processing module, based on said data signal, outputs said control signal according to the low light mode, characterized in that the pyroelectric sensing module is configured to start to sense only when the signal data is according to the low light mode or the fill light mode.