License plate location is one of the key technologies in license plate recognition system. By preprocessing the license plate image to remove the interference noise, this paper uses the method of interlaced scanning and the mothod of rectangular window searching to location the license plate's top boder, bottom boder, left boder and right boder. So it greatly improves the speed of license plate location. This paper also proposes that the changing of location area can judge the tilt condition of the license plate and gives out a correction mothod of the tilt license plate. The experiments show that this algorithm is simple and efficient.