Abstract: According to the Charactes of the modern economic systems, we designed an Optimal model System, and Studied on the equilibrium with its realization of the three main markets: product market, financial market, and Labour market, by means of the model system and the duality Theory. Furthermore,we showed the basic Conditions for realizing the equilibrium of the three main markets.

Key words: Duality Theory, Model Eystem, Economic Equilibrium