Abstract: Based on motivation analysis of the participants in the knowledge question and answer group,this paper studies the incentive mechanism that is in line with their participation. This paper gave a brief introduction on the related theory,put forward the basis of our research hypothesis,in order to build a conceptual model of knowledge network,and then took crowdsourcing platform players as research subjects,using a combination of questionnaires and online interviews to investigate the motivation of knowledge type crowdsourcing participants and carry out an empirical research using structural equation model. The empirical results show that participants' immersion in pleasure,self-improvement,external rewards and perceived benefits have a positive relationship,so do execution cost and perceived risk;there is a positive correlation between perceived benefit and perceived risk while perceived risk and the willingness to participate have a negative relationship;the willingness to participate has a positive effect on participation behavior. Finally,the incentive mechanism based on the characteristics of the Internet crowdsourcing model is put up,which is based on the analysis of the motivation and the degree of influence on participants.