In order to improve its behaviors, a behavior model for public participation in River Chief System of China is established based on the MOA theory, and its influencing factors and action path are analyzed. The research results show that the public participation motivation, including demand of water resources, health demand, sense of ownership responsibility and self-realization demand, positively affects their participation behaviors. The participation opportunities, including legal system, participation mechanism, information disclosure and material rewards, positively affect their participation behaviors. The participation ability, including professional knowledge ability, information acquisition ability and communication ability, positively affects their participation behaviors. In addition, the participation opportunities have an important positive impact on the participation ability, the opportunity of public participation has the greatest impact on the participation behaviors, followed by the participation ability and the participation motivation. Finally, some systematic suggestions are put forward to improve the public participation behavior from three aspects: ensuring public participation opportunities, establishing the promotion mechanism of public participation ability and stimulating public participation motivation.