The leadership of government, departments, the whole society to participate in" the Chinese characteristic the anti-AIDS work mechanism, as a folk grassroots social organization edge specific populations and the unique role has shown positive effects. This article is based on the L city social organization -- MSM organization to participate in AIDS prevention and control in practice on the basis of field investigation, description and analysis of MSM internal structure function as well as how to use organizational capital to participate in AIDS prevention and control act.