Facial expression recognition technology is a branch of face recognition technology. With the development of artificial intelligence technology and computer technology, expression recognition technology can analyze the image to determine the psychological emotions of the recognized humans and realize the computer’s understanding of facial expressions. Moreover facial expression recognition can fundamentally change the relationship between people and computers so that computers can better serve humans and achieve better human-computer interaction. In applications, facial expression recognition technology is used in psychology and intelligent robots; and it has great potential application value in intelligent monitoring. For example, in the retail industry, it is possible to identify the customer’s expression to obtain his preferences for products or to intelligently recommend suitable advertisements through expression recognition to achieve precise marketing and interactive experience.