Coal mining is an integrated trade which involves the geology, well ventilated, transportation, electricity and environmental protection and so on. The mining industry has labor intensity, bad work condition, many harm factors. Each kind of virulent noxious gas, coal dust, fire, electromechanical device are all immediate danger to operate personnel's safety and healthy. Well-balanced and suitable ventilation is the postulate to keep the health of underground worker and the safety of the production. We take air quantity of laneway as the research emphasis, considering the release of state regulations on coal min. We figure out the optimum area of air quantity via building the optimization programming model, and realize an actual case study to interpret the process of the probabilistic risk analysis (PRA) with statistic theory. We take the theory to the actual production. We establish a MIS base on the theory. In the process of establishing the system, we use the object-oriented analysis method and the B/S structure, take JAVA as the development kit, and realize the risk analysis system. Then the risk manager can take the corresponding monitoring measure.