Abstract: User loyalty is the core competitiveness of virtual community and loyal user is the main benefit source. The evaluation index system of user loyalty is an important content in user loyalty evaluation research. Based on the principle of loyalty design, a virtual community user loyalty index evaluation system was established by combining qualitative and quantitative methods, and using the AHP to calculate the weight of user loyalty index, and the concrete method to calculate the evaluating value of loyalty evaluation was given. Combined with a specific virtual community, it also verified the process of loyalty calculation. The conclusion of the study can be used as the basis of subdivision of users in virtual communities and provide value to users on this basis.