分析了安全的科学含义，引入了"灾事"的概念，指出安全科学的研究对象就是灾事，并进一步探讨了灾事的类型以及各类灾事之间的关系。阐述了构建安全科学的必要性和可行性，并从一个新的角度分析了安全科学的内涵以及构建安全科学的基本思路，论述了安全科学技术体系的层次结构。

The scientific meanings of safety are analyzed. The concept of “zaishi” is introduced and the fact that it is just the research object of safety science is pointed out. The types of “zaishi” and their relationships are also discussed, based on which the necessity and feasibility of the construction of safety science are expatiated .The connotation of safety science and the basic approach of the construction are analyzed in a new point of view. Finally，the hierarchy of system of safety science and technology is discussed