Community social organization，also known as “the 3rd power”，is the carrier for community residents to realize the action of self-management and self-service. Thus to cultivate and develop community social organizations has become the hard-core of community construction in China. From the perspective of social work，this article firstly analyses the connotation，characteristics and types of community social organization，then，probes into the social function of community social organizations in terms of social constriction，social service and social residents self-management via taking some teenagers education association in Xicheng district of Beijing as a case study and finally provides beneficial suggestions for the development of community social organizations.