The economic system is a typical complex system, which consists of various kinds of economic agents. In consequence, the according research methods should focus on new tools, which adapt to complex system study, instead of the traditional equilibrium static modeling methods. In this paper, we set up a simple market economy MS model based on the foregoing methods. This paper designs agent models for four different nodes agents, and enterprise, government and foreign trade actions, and makes an economy simulation in which the author apply created MS modeling to simulate the basic status. We have made policy recommendations, that the Government should continue to steadily promote the reform of the market economy system, assure their roles well, reduced the unnecessary intervention on the economy, meanwhile improved own macroeconomic regulation level to prevent surplus macroeconomic fluctuations, and promoted the healthy development of the economy. The principles and steps, which should be followed in agent-based complex systems modeling and simulations is established.