Combining image processing and artificial neural network technology, a new diagnose method of soybean leaf diseases has been proposed, which identified the methods of division algorithm and eigenvalue computation, meanwhile, established a three-level neural network model to identify the diseased spot areas. According to the characteristics of soybean leaf disease, a new diagnose method has been formed, through extraction of geometric features, color and texture feature, which provided reference to Remote Intelligent diagnosis of soybean leaf disease.