Abstract: It is very important for crowdsourcing system to analyze crowdsourcing workers’ collaborative behaviors. In this paper, the evolutionary process of crowdsourcing quality was studied based on classic hierarchically-organized mode. By establishing an evolutionary game model for crowdsourcing task collaboration among different virtual organizations, the evolutionary stability of crowdsourcing systems was analyzed and the dynamics of crowdsourcing workers’ behaviors were discussed macroscopically. The key factors affecting the evolution of crowdsourcing system, including the economic benefits, consumer utilities from completing crowdsourcing tasks and risks from insecure participating, were suggested and how the factors work was presented. All these results together provide the theory basis for designing quality control methods of crowdsourcing system.