Based on the investigation and examination on the technology and products of dimming LED light source for indoor illumination, a wall switch style of LED dimmer and dimming driver were designed. To lower down the interference to the power gird, the controlling mode of triac"s conducting angle was eliminated. Instead, the dimmer sends a 2~5 kHz pulsed dimming signal with small voltage (~15V) along the single power line, which is detected and demodulated by the receiving circuit of the driver to adjust the PWM dimming grade of the driving circuit. After the dimming operation, the dimming grade can be maintained stably while the dimmer maintains turning-on of the whole period of the power wave. The operating current of the dimmer is provided via current coupling and divided voltage respectively in the turning on and off states of the light source. The dimmer and dimming driver have low static power consumption, high power efficiency and power factor, as well as low harmonic wave distortion of the input current.