Facial expression recognition is to make computer understand facial expression according to human thinking, which is an important part of human-computer interaction. However, with the rapid development of deep learning, the research of deep learning technology in facial expression field has become a research hotspot, so the application and achievements of deep learning technology in facial expression recognition were analyzed. Firstly, several common expression data sets were summarized; then, the expression recognition methods based on deep learning were classified from two aspects of feature extraction and feature classification, and several network improvement methods in expression recognition based on deep learning were analyzed from the aspect of network improvement; finally, the challenges and future development in the field of expression recognition were described.