Abstract: Online reviews don't play the same roles in supporting the purchase decisions for users, only the ones affecting users’ purchase decisions have usefulness. This paper used structural equation model to explore the factors affecting the usefulness of online reviews and its mechanism, so as to provide reference for the research. Based on literature review, the model was constructed by adopting the influence of perceived authenticity, perceived value and perceived authority on the perceived usefulness.The data was collected by questionnaire survey and processed by AMOS software to verify the fitting performance and make validation analysis, and SPSS software to test intermediate effect. The model fitting degree was high, which illustrated that the construction of the model had certain persuasiveness: perceived value had partial mediating effect, and the perceived authenticity affected the perceived authority and finally influenced the perceived usefulness of online reviews.