Abstract: Using the combining methods of computer simulation, theoretical analysis and on-site practice, the paper establishes of unascertained measure optimization model for mine ventilation system, proposes the method of using confidence to identify optimal solution，and membership level of every solution is obvious. Determining the right weight by information entropy is more objective. The model has been applied in selecting the best ventilation system modification scheme of Liudong Coal Mine，which determines the optimum solution effectively. The optimal solution has been applied in Liudong Coal Mine, which not only improve the problems of the original mine but also get a lot of economic benefits.