With construction projects continuously becoming more massive and complex, risk factors have been consistently increasing. To achieve a successful project, it is very important to identify and cope with such risk factors. Therefore, the purpose of this study is to suggest plans of reducing risk, not only for describing the drafting process for construction planning but also for systematically organizing constraints and risk factors in earth work, foundation work and reinforced concrete construction. To achieve these objectives, this study 1) analyzes previous theories about risk classification structure, 2) performs a case study of an actual project to embody the problems of safety management by analyzing the results of an interview with a construction engineer. In conclusion, the following factors were systematically organized: 1) characteristics of construction site (purpose, structure, floor, etc.); 2) the actual application conditions of the main construction methods; 3) the relationship between constraints and risk factors.