As an important role of social governance，social organizations can play a better role in rural revitalization because of their commonweal and professional characteristics. In the process of participation，the functional localization of social organizations not only affects the quality and effect of their participation，but also determines whether they can continue to be participating in rural revitalization. Takes social organization S participating in the revitalization of village as an example，this report analyzed the evolution process of social organization S from providing help timely to make things better，and then to excessive participation，and finally to be exit from the project. The inspiration of this case is that in the process of social organizations participating in rural revitalization，they can provide timely help or make things better，but they must not participate too much，otherwise they will be out. The main functions of social organizations in rural revitalization should be localized as the supplement of the government rather than the replacement，the assistant of village cadres rather than the opponent，and the fire extinguisher rather than the igniter of villagers.