Abstract: Based on the gas geology information of combined mining faces of Chenjiashan Coal Mine that contains coal and oil gas,it is researched that the main geologic and productive factors controlling gas gushing quantity of mining faces using the relating analysis method of gray system theory.The BP network model of prediction of gas gushing quantity for combined mining faces is established by means of BP network method of ANN theory.The error analysis and practical use show that combining relating analysis method with BP network method to predicting gas gushing quantity of mining faces is a feasible method.