An evolutionary model of industrial dynamics （EMID） based on NW model is proposed in this paper. By EMID, the competing dynamics in the industry, which allows new firms＇ continuous and random entry, is analyzed. The paper studies the evolution of industry structure and the interaction between firms＇ investment decision-making, R＆D strategies, technique transformation as well as other aspects of industry characteristics. The evolution of industry structure is simulated by computer experiment, and simulation result shows that EMID can represent stylized facts of industry evolution and that EMID is a simple and relative general model of industry evolution