为构建符合我国城市轨道交通运营特点和实际的事故分级理论，明确城市轨道交通运营安全事故分级的细化要求，通过分析国内有关城市轨道交通行业主管部门和运营单位的事故分级现状，从层级架构和分级标准两个维度，总结提出了单层级与双层级，以及后果型、枚举型与组合型的事故分级方法，并对不同分级方法的优缺点和适用性进行了对比分析。同时，从事故分级方法选择和评价角度，提出了一种能够用于分级方法完整性和有效性判定的事故分级体系。结果表明，单层级后果型分级方法更适用于行业主管部门，多层级枚举型或多层级组合型更适用于运营单位；事故分级体系应当至少包括伤损级、影响级和现象级3个层级，对应的事故后果严重程度依次降低。

In order to construct an accident classification theory that conforms to the characteristics and actual situation of urban rail transit operation in China, and to specify the detailed requirements for the classification of safety accidents in urban rail transit operation, by analyzing the current status of safety accident classification in relevant authorities and operating companies, some accident classification methods were summarized and proposed in two dimensions of hierarchical structure and classification standards, including single-level and double-level, as well as consequence, enumeration and combined accident classification methods. The advantages, disadvantages and applicability of different classification methods were compared and analyzed. At the same time, from the perspective of selection and evaluation of accident classification methods, an accident classification system that can be used to evaluate the integrity and effectiveness of the classification methods was proposed. The result shows that the single-level consequence-based classification method is more suitable for industry authorities, the multi-level enumerated and multi-level combined type are more suitable for operating companies; the accident classification system should include at least three levels of damage level, impact level and phenomenon level, and the corresponding severity of accident consequences is decreasing in turn.