In the new era, the uncertainty and mutability of network society greatly subvert the evolution of major engineering social contradictions and pose a new challenge to the design of traditional closed major social contradictions resolution mechanism. Public participation has an important guiding role in dealing with this challenge. This paper analyzes the social conflict dilemma of major projects through the crack hypothesis. The results show that establishing a participation system which matches public participation level is the key to solving the dilemma. Citizen participation maturity is taken as a tool for dividing citizen participation leveland citizen participation is divided into three levels according to low, middle and high level. The paper introduces the network governance theory and designs a public participation matching network mechanism, which means to establish the public participation mechanism of “ Government Leading-Community Participation”, “ Government Guidance Social Organization Intervention ” and“ Cooperation between Government and Social Organizations ”. Such mechanism can guide public participation to self-dredged, self-governed and self-resolved social contradictions and then form a new network governance pattern of “common construction and sharing by the whole people”.