Abstract: Social co-optation mechanism is an important institutional design in national governance system. With the popularization and application of social media, compared with the absorption of social organizations and social elites, there is a positive trend in the absorption mechanism for ordinary people. By observing the operation process of L town using WeChat group to carry out social mobilization, this paper analyzes the operation mechanism of administrative co-optation of the public. The absorption mode for ordinary people is defined as "direct connection absorption", which shows that a "group" forms by "class", namely, the "common law" is used to find reliable "own people". It is found that there is a "differential order pattern" in social co-optation, which forms a progressive process of "quasi-administrators-active cooperators-subordinates to managers". The core operation mechanism is an infiltration mechanism and an elimination mechanism. Through identity recognition and behavior identification, we can find "our own people" among ordinary people with the purpose of infiltrating into the society to grasp the real information or help to complete some things. "Social co-optation 2.0" in the new media society is obviously different from the traditional co-optation mode and provides a new analytical perspective for creating good interaction between the state and the society.