Abstract:To find out the evolution law of the interactive process between the third party pollution treatment companies and governments, this paper, using the method of evolution economics, builds a payment matrix of the third party pollution treatment companies and governments, analyses the evolution model of the associations between the third party pollution treatment companies and governments, and shows the parametric diversity of decision-making and the effect of changing initial condition on evolution result by numerical simulation. The research reveals that the evolution system of the third party pollution treatment companies and governments converges on two types of patterns, the converging probabilities change notably with the changing of cost and benefit; the research directs the system how to jump out of the locked status, and points out that spontaneous evolution of association pattern between groups of the third party pollution treatment companies and governments is dependent on relative payment of various tactics; the government should enact strict environmental regulations; the third party pollution treatment companies should broaden their earnings path.