In order to evaluate the user experience more objectively and expand the way of user research, the expression recognition technology is introduced to optimize and explore the existing user research methods. Taking reading app as research carrier, expression recognition and convolution neural network algorithm as technical means, through the design of human-computer interaction experiment, it is applied in the process of user research, and the mapping relationship between user's facial expression and user's subjective satisfaction is established.Aiming at reading app "X", this paper carries out a two-way design research based on facial expression recognition technology and traditional questionnaire interview, and obtains the effectiveness and feasibility of objective measurement method of user satisfaction based on expression recognition technology by using comparative verification method, and then explores the advantages of expression recognition method in user research. The user research method based on expression recognition technology has certain universality in product interaction design. By identifying and analyzing the dynamic changes of facial expressions when users interact with the product, the user experience evaluation can be more objective and easier to interpret, and the product interaction experience problems can be accurately located. In addition, it provides new ideas for user research and understanding in the field of design, and provides theoretical and practical reference for the cross integration of expression recognition technology and product design.