Abstract:     Green supply chain has become a new focus of cooperation between government and enterprises. With the development of market economy, the market competition in the 21st century will rise from the competition among enterprises to the competition between supply chains, which is a higher level of expansion. Supply chain, as the main body of manufacturing system to complete the whole material flow process, plays a vital role in manufacturing activities. Establishing a "green" supply chain is an important means to achieve green manufacturing. Green supply chain management mode is to integrate environmental awareness into supply chain management, increase "green factors" to improve resource utilization and reduce environmental pollution. It is a new development direction of supply chain management. Green supply chain will bring higher production costs to enterprises，including pre-research investment, manufacturing process investment and environmental recovery investment for implementing green supply chain management. Effective subsidy policy formulated by the government can promote the promotion of green supply chain, but at present, most of China′s legal policies are based on planning and guidance. The lack of government subsidy policy which can effectively alleviate the pressure of production cost of enterprises, causes the slow promotion process of green supply chain. For governments and enterprises, how the government adopts appropriate subsidy policy to guide the green supply chain, and how to make the right business decision is the key to achieve the mutual benefit，but also an urgent problem to be solved. Therefore, exploring the game behavior of government and enterprises in green supply chain has certain theoretical significance and practical value.
    So far, scholars at home and abroad have carried out extensive research on the game behavior of green supply chain and its related participants. Most studies neglect the role of government and its interaction with the decision-making of supply chain members to varying degrees, or only regard government as a parameter in the game model. Few scholars regard it as a stakeholder in the game model. In fact, the government and enterprises also have game behavior in environmental practice, and the ultimate goal is to maximize profits.
   Therefore，this paper takes the government and enterprises in green supply chain as the research object. Evolutionary game theory is often used to study the existence and evolutionary stability of main body behavior. System dynamics can quantitatively analyze the impact path of key factors affecting government-enterprise participation behavior. In view of this, this paper combines evolutionary game with system dynamics model, and assumes the participating individuals are limited rationality to explore the dynamic process of government and enterprise strategy selection in green supply chain. Firstly, the evolutionary game theory is used to construct the behavior of two stakeholders (i.e. government and enterprise) in the selection when they participate in the green supply chain. Then, the evolutionary game relationship of the two stakeholders participating in the behavior of green supply chain is discussed and the equilibrium stability is analyzed. Next, in order to explore the dynamic evolution process of the participating behavior selection of government and enterprise, the system dynamics model is further established. The system dynamics (SD) model and vensim software are used to simulate the game strategy change and its evolution trend under different parameters. The main conclusions are as follows: (1) There exists a balanced strategy in the game of participation behavior of government and enterprise in green supply chain, i.e. both participate or do not participate. (2) The degree of active participation of game players in green supply chain is influenced by the initial willingness ratio. Active government subsidy policy, reasonable subsidy intensity, high green management level of enterprises and good quality of green achievements have positive effects on the healthy development of green supply chain. (3) There is an effective interval for government subsidy, so the government should grasp the reasonable subsidy to prevent the healthy development of green supply chain from being hindered by the profit-seeking mentality of enterprises.
   In addition, in order to enable the government to guide enterprises to actively participate in the practice of green supply chain management, so as to better promote the development of green management, this paper also puts forward the following policy recommendations:
   Firstly，to formulate a scientific long-term incentive policy to improve the green awareness of supply chain management. At the same time of giving full play to the incentive role of subsidy policy, we should enhance the environmental responsibility consciousness of enterprises, so that both government and enterprises can fully participate in the green supply chain. The government′s subsidy policy and the initial willingness of enterprises to participate in the implementation of green supply chain management are increasing means it is more conducive to achieving the ideal state of maximum profits for both sides and to achieving higher social well-being.
   Secondly, creating conditions for enterprises to improve the quality of results and increasing comprehensive benefits. As an incentive in the green supply chain, the government should focus on improving the quality and efficiency of development, create a green environment for enterprises and favorable conditions, catalyze high-quality construction results, and maximize the comprehensive benefits of both sides. In addition, in the process of formulating the corresponding subsidy policy, the government should not only transform the green achievements into promoting policies in time to create more favorable conditions, but also do a good job in relevant research to avoid the loss of profits caused by the improper direction of subsidies.
    Thirdly, encouraging the adoption of efficient green production technologies to reduce management costs. As far as green supply chain management is concerned, the relevant management technology of domestic enterprises is still in a backward state. The government should guide enterprises to refer to mature experience, adopt advanced technology, and achieve a high level of green upgrading on the basis of strict control of moderate management cost, so as to form a green supply chain management system with low cost and high profit.
   Fourthly, grasping reasonable subsidy input and mobilizing the enthusiasm of upstream and downstream enterprises to participate. The subsidy input has an effective boundary. Only by grasping the strength can we give full play to the positive impact of the subsidy policy on the development of green supply chain.For the situation that the government subsidies are obviously too large, we should adjust the subsidy strategy in time, reduce the input cost appropriately, and focus on optimizing the subsidy cost structure, so as to prevent the negative impact of the original positive incentives from being offset.

Key words: green supply chain, participation behavior, government subsidy, evolutionary game, system dynamics