Abstract: Competitive neutral, business environment and the reform of state-owned enterprises have an inherent fit. Based on the dilemma and difficulties of the mixed ownership reform of state-owned enterprises in Northeast China, this paper models the behavior of shareholders with different property rights in the mixed reform under the northeast characteristic business environment. With the assumptions of complete rationality and incomplete rationality of shareholders separately, two paradigms of both static equilibrium and evolutionary equilibrium are used to analyze how the formal top-down policy system and the informal bottom-up behavior effect the productive cooperation and non-productive invasion of the shareholders. The conducted relative return and inspiration structure will be quoted to depict the efficiency and characteristics of the mixed ownership reform，and then forward corresponding policy recommendations can be proposed.

Keywords: State-Owned Enterprises; Mixed Ownership Reform; Business Environment; Neutral Competition; Evolutionary Equilibrium