As the evolution of automobile industry, the application of cars has been gradually extensive. Nowadays, automobiles have been an essential part of modern society .The development of car equipments has also been accelerated by the growing popularity of the automobiles. Meanwhile, if these equipments are not regulated rationally, they also rouse extra consumption of power stored in car batteries. GPS system, as an example, causes unnecessary consumption while the automobiles are at rest. As the power loss of automobiles may cause series of dangers, such situation should be avoided. The article provides a feasible way to make an intelligent control on power supply system of automobiles through AVR single chip programming. Thus helps regulate the usage of the car batteries. From this, automobile securities can be enhanced.