Abstract: 【Purpose/significance】This paper explores the mapping relationship between user motivation and behavior of academic so⁃cial network,deduces user motivation from behavior data,and constructs group portraits based on motivation,so as to provide guidance for the platform to locate user groups and mine demand preferences【. Method/process】Firstly,the paper analyzes the projection process of academic social network users' motivation.and clarifies the types of motivation and the projection expression of behavior under dif⁃ferent motivations; Then the overall process of user's motivation portrait is designed.Finally,taking the small wood insect community as an example,the corresponding behavior data are collected for the experimental analysis of motivation portrait【. Result/conclusion】The results show that the sample can be divided into five groups.By comparing the cluster center with the average users,the group charac⁃teristic labels can be summarized from the perspective of motivation.and the user motivation and demand preference can be interpret⁃ed【. Innovation/limitation】We have made an innovative attempt in changing the way of obtaining users' motivation and giving full play to the guiding role of motivation research in operation practice.but we need further research in fine-grained behavior data collection and comparative analysis in different fields.