The Chinese social service agency think tanks can be the non-profit legal person who conducts public policy service consultation and advice using non-state-owned assets. In the vertical direction，it has experienced a four-stage development process. In the horizontal direction it has three development characteristics. Based upon two dimensions of “service mode” and “research process” of the Chinese social service agency think tanks，These operation modes can be divided into different types. By the “service mode”，it can be classified into the policy service mode，the policy analysis mode，and the theoretical service mode；by the “research process”，it is divided into the research project source mode，the research project operation mode，and the research result output mode. And，a distinction is made between the specific types of each mode to reveal the overall development of the social service agency think tanks.