Abstract: The objective of public services contracting is to improve the efficiency of public funds and provide better public services for the public through specialized operating of business or social organizations. However, achieving this purpose needs collaboration among the government, contractors and the public. By constructing evolutionary game model and applying system dynamics simulation analysis, the conclusion shows that, in the public service contracting: (1) the tripartite will eventually reach an equilibrium (government regulation, public participation, contractors effort), to which public participation contributes significantly; (2) Strategic selection of the tripartite is more sensitive to the change of related individual constituents of exogenous variables, but in the end, the policy choice depends on the comparison among a number of variables, so the government should handle the relationship between the various stakeholders; (3) Whether contractors make effort or not has no direct impact on the public selection, so the government should take appropriate measures to punish the contractors who do not work hard. These findings will have positive reference for China's current public service contracting development.

Key words: public service contracting, evolutionary game, system dynamics, collaboration