With the development and maturity of intelligent buildings, energy conservation become a trend, lighting control systems are becoming increasingly popular. At the same time with the rapid development of electronic technology, microcomputer as a subject and core for embedded control systems, instead of the traditional conventional electronic circuits of the control system, based on single chip microcomputer control system has been widely used in intelligent building. This text directs against the power consuming wasting phenomenon of public place, regard AT89C51 as the core, propose a measurement for Pyroelectric infrared sensor and light combination of intelligent lighting control system. By judgment on the light intensity and indoor if someone automatically switch lights, achieve the purpose of energy saving.