The definition and diagnostic criteria of sepsis are constantly updated in recent years, which is an inevitable requirement for optimizing clinical diagnosis and treatment of sepsis, but it brings new challenges to clinical practice at the same time. This paper retrospectively reviews the changes in diagnostic criteria in sepsis 1.0, 2.0 and 3.0 version, and finds that relevant definitions in sepsis guidelines published at home and abroad are insufficient in varying degrees. Over the past three decades, definitions have been changing constantly, different versions of definitions may be adopted in different literatures, which is easy to cause confusion in sepsis knowledge and data, and may result in delayed treatment or blindly expand treatment of clinical sepsis. Diagnostic criteria and epidemiological data of sepsis still need to be further explored and improved, China also needs to consider formulating a series of recommendations that are easy to be measured and conducive to defining patient diagnosis and management.