As the dimming method of single power line based on the switch on-off control technology only provides 4-grade brightness adjusting for LED lights and has requirement for the switching operation time, proposes a method of the single power line brightness control circuit, the luminance signal receiving circuit and the brightness control drive circuit to achieve LED dimming. The method adopts the bidirectional thyristor positive and negative half wave to control phase-shift trigger, gives the LED lamp control signals of increasing or decreasing brightness by single power line and identifies the brightness control signals by MCU. The micro controller output duty ratio can adjust the PWM signals to control LED lamp brightness changing between 0 and 100% with 1% step value.