Abstract: Because of being based on expected utility theory, traditional game theory has certain limitations. Prospect theory is the best tool to characterize risk and make decision under uncertain environment. In this paper prospect theory is taken into the analysis framework of PT game, the weighting function of players is employed to build the perceived benefits matrix, which can replace the payoff matrix composed by the traditional payoff function. The mixed strategies Nash equilibrium of PT game is solved. The equilibrium strategies of participants are proved to be not only affected by the payoff parameters, but also influenced by their reference points, loss aversion, diminishing sensitivity and the curvature of their weighting function. The psychological heterogeneity is the reason why different people choose various strategies when facing the same condition. It shows that in the social welfare game, the probability that government choose help strategy has a positive relationship with the loss aversion and diminishing sensitivity of the unemployed, while has a negative relationship with the curvature of their weighting function.