Throughout the history of agricultural development, crop pests and diseases have always been one of the main obstacles hindering the development of agricultural economy. The crop disease identification system based on digital image processing technology had the characteristics of fast, accurate and realtime, which can help the farmers to take effective prevention measures in time. As an important technical means in the field of image recognition, deep learning has broad application prospects. The research progress of crop pest and disease image recognition technology in deep learning field in China and abroad was reviewed. The significance and necessity of deep learning technology research were clarified. The training samples of deep learning technology in image recognition research were large and the model structure was complex. Complex image recognition accuracy was low. It was proposed that improving the recognition accuracy of complex images would be the development direction of future research.