“命案必破”成为刑侦工作的理念,因而命案侦破工作在领导重视、组织形式、落实程度上都有很大变化。一起命案发生后,经过现场勘查、尸体检验、初步调查访问,侦技人员都要做到一起汇总信息,并进行分析讨论。有些疑难案件在侦破过程中还要多次进行讨论。在多次分析讨论会上,发现有些意思很难表达,有些概念由于定义不清,讲述者与听众理解不一致,因而需要对一些问题进行阐述,以便达成共识。命案分类的方法有多种,如:按凶手性别、按作案人数、按作案方式、按作案的后果以及对社会的影响等等,都可进行分类。本文从侦查破案角度出发,主要按作案动机进行分类, “Homicide must be broken” has become the concept of criminal investigation work, and therefore homicide detection work in the leadership attention, organizational form, the extent of implementation have greatly changed. After a murder occurred, after site investigation, body test, preliminary investigation and interview, investigators must do together to summarize the information, and analysis and discussion. Some difficult cases in the detection process also need to be discussed many times. In many analysis seminars, I found it difficult to express some of the meanings. Some of the concepts were ambiguous because of the unclear definition and the disagreements between the narrator and the audience. Therefore, some issues need to be elaborated in order to reach a consensus. There are many ways to classify murder cases, such as: according to the murderer’s sex, according to the number of committing the crime, according to the mode of committing the crime, according to the consequences of committing the crime and the impact on society, etc. can be classified. This article, from the perspective of investigation and detection,