A precise light compensating method integrated with real-time environmental monitoring, specific wavelength light complementing and quantitative decisionmaking was proposed. Based on feedback control mechanism, a quantitative decision-making algorithm was put forward. Using a single chip as the central control unit, the light complementing value was accurately calculated based on the environmental temperature and the difference between target and real-time values of light intensity of red and blue light. Light intensity output of LED was adjusted by PWM duty cycle to meet the demand of light complementing. Experimental results show that the system has achieved quantitative multi-waveband light complementing. And it realized the energy saving of 54% and 83% respectively to filament lamp and fluorescent. With the same LED, the system has an average energy saving ability of 30% or more compared to the existed LED light compensating system, and the energy saving rate fluctuated at different light quality thresholds and environment conditions.