The supervision behavior of government regulation is the inner source of project quality government supervision effectiveness, The essential characteristics of project quality government supervision running are double principal-agent mechanism. Multiple principal-agent research at home and abroad are limited to the same object, abstract subject behavior between strategy and balanced process, government supervision over the quality engineering has two layers of principal-agent differences and the second level agents, the complex organizational structure of the monitoring group, to explore its agent chain multi-level incentive mechanism will be conducive to double principal-agent theory.Based on the construction main body structure and the economic contract, Analysis the principal-agent relations and characteristics of construction project quality government supervision, building and simplifying the project quality government supervision agency chain; construct the principal-agent mechanism model of project quality government supervision with Holmstrom and Milgrom parameterization method, based on the analysis of agent chain structure to simplify the incentive mechanism model, through the game model to get the incentive parameters of project supervision. Results show that: Incentive coefficient β is r、σ² and b decreasing function, Project quality forming process of the larger the variance, the agent is more afraid of hard work, the corresponding risk is smaller. Quality supervision team effort a_ik=β/bΛ_ik² is proportional to the β, and is inversely proportional to the cost coefficient and engineering contracts, enhance the quality of supervision and professional level is helpful to reduce its quality supervision cost coefficient; set up quality grading evaluation mechanism is the precondition of incentive mechanism; quality supervision cost will affect its quality supervision effort level (a_ik=β/bΛ_ik²), quality supervision is inversely proportional to the cost and the ability of supervisors; if the government supervision department keep expense proportion is 1-ρ, adjusting incentive mechanism coefficients is ρδ and ργ, the government objective function can achieve the optimal. When take no account of the project contracts, it can simplified to unit principal-agent model, β=1/1+rbσ². In addition to the incentive mechanism, the work together of the punishment implementation mechanism, reputation mechanism, insurance mechanism and the rating system make for ensure the steady rise of engineering quality. Project quality government supervision agency chain and multi-level incentive mechanism research will be for engineering quality and government supervision coordination incentive measures and operation mechanism optimization to provide theoretical support and serve as a reference for other public goods regulatory incentive theory.