Abstract: 【Purpose/significance】This study aims to investigate the influences of peer effects on users´ knowledge contribution behav⁃ ior in social Q&A community.【Method/process】From the perspective of peer effects, a theoretical model of factors influencing users´ knowledge contribution behavior in social Q&A community was developed. 8667 valid samples were obtained by crawling user data from Zhihu, and negative binomial regression analysis was conducted using R software【. Result/conclusion】The results show that num⁃ ber of users´ followees is positively related to quantity of solicited knowledge contribution, and negatively associated with quantity of voluntary knowledge contribution. Also, number of users´ followers has an inverted U-shaped relationship with quantities of solicited and voluntary knowledge contributions. In addition, sense of belonging positively moderates relationships among users´ followees, fol⁃ lowers and quantity of solicited knowledge contribution. Furthermore, core user identity negatively moderates the relationships be⁃ tween users´ followees and quantity of solicited knowledge contribution as well as users´ followers and quantity of voluntary knowledge contribution.【Innovation/limitation】From the perspective of peer effects, this study reveals the inverted U-shaped relationship be⁃ tween number of users´ followers and knowledge contribution behavior in social Q&A communities with objective user data. Also, it identifies the differences in knowledge contribution behavior of different types of users.