Taking the communication power of the academic journals’ Wechat public number as the research sample, this paper studies its evaluation index and method, which can provide reference value for the promotion of academic journals’ Wechat public number. The paper uses the Analytic Hierarchy Process to construct the evaluation index system, uses triangular fuzzy numbers to make the index weights, then builds the communication power model, defines the value-setting method for index and selects the “library and information service” for empirical analysis. After the empirical analysis of evaluation index, model and the validity of the studied indicator value, the paper finds that the communication power of “library and information service” is in general and that it has both the general reason and the special reason. These issues are also the key to enhancing the communication power of the academic journals’ Wechat public number.