As a first-level scientific discipline listed in the Chinese National Standard GB/T13745-1992, the Code and Classification for Disciplines, safety science has its own research object, i. e. the accidents, incidents or near misses occurring in a wide range of human activities. Its aim of research is to prevent all accidents and control loss caused by accidents. By combination of fundamental principles of accident prevention and its investigating tools, which includes natural sciences, e.g. mathematics, physics, chemistry and social sciences, like managerial science and psychology, a system of applied safety sciences has been formed. And, when this system is applied in different fields, a different system of sub-system of safety sciences can be created, e. g. public safety, city security and safety, occupational health and safety—a most sophisticated subject in safety science. By careful examination, comprehensive analysis of many contributions by scientists in accident and injury prevention field, 6 basic concepts and 3 axioms have been identified by the authors, which can be used to structure the frame of safety science.