Abstract: In order to identify the maize seed purity efficiently, after researching on image processing methods and classification algorithm in terms of the image characteristic of maize seed, a purity identification calculation based on discrete wavelet transform(DWT) and BP neural network was presented. Through this method, the RGB color model character parameters of the maize seed crown part were obtained, then the three color values were processed and analyzed by the two-level DWT. The average of every band was selected as the input samples for BP neural network, and purity identification results of maize seed as the output samples of neural network. Results demonstrated that this method can identify the maize purity effectively with accurate identification rate reaching 94.5%.