The traditional license plate localization algorithm uses the gray image texture feature, the texture feature of gray image features and limitations bring great difficulty in getting a license plate localization algorithm. In view of this, the color of license plate localization algorithm based on the moiré principle is proposed. Firstly, two-dimensional wavelet decomposition for image, sliding windows is small ripple bedding features of images; And at the same time convert low-frequency subgraph RGB color components as HSV color value, extract color feature, and get a comprehensive feature vector; Secondly, wavelet variations positioning license plate area; Finally to locate the license plate positioning results of late correction processing and output. The algorithm adopts the comprehensive characteristics of localization, overcomes the drawback of using single feature localization and limitations, an can be seen from the results of this algorithm can accurately extract the license plate location information from the background image.