Abstract: The coal is an important strategy resource in our country,it is important for guarantee our country's energy safety.In this text,we aim at the excessive competition problem in coal factory and applied the game theory as analysis method to research the big mine and small mine `s strategies and their pay-matrixes under different price,it express that it is the difference between their MC(marginal cost) what result excessive competition,Therefore,the over low MC of the small mine not only is the reason what due to serious wasted to coal resources,but also cause the excessive competition.In the end,the author advise to tax for the expenses of ecological environment and enhance the mine's management efficiency so as to increase its threshold and establish a preface compete industrial structure.