Abstract: In this article, BP network learning algorithm is improved by using momentum and genetic algorithm after analyzing the defects of the BP network learning algorithm.So the convergence rate of BP network is speeded up greatly.The vehicle license plate character image is segmented and feature is extracted by edge detection using sobel operator.And then license plates of cars are automatically recognized by using improved BP neural network.This algorithm can improve the speed and accuracy for the automatic identification of the license plates of vehicle.