High Speed Railway is a huge traffic system which is operated organically combining all the element : vehicle, track. Electricpower, signal/communication, operation, etc. Safety level has been improved steadily by learning lessons from past accidents. But with rapid progress in high-speed, massive, high-frequency transit fresh idea of accident prevention is now in order. In quest of effective and efficient countermeasure, we aim to establish an adequate safety evaluation/management method. Our proposals are basic concept relating to safety, analysis of reliability, quantitative safety evaluation through multivariate analysis. Based on these method, we developed a safety management supporting system.