Abstract: The existing failure analysis system is explored with the expectation of its reshaping and development. Firstly, the various definitions of failure are reviewed. Based on this, a new definition of failure is proposed, thereby gaining a profound understanding of the nature of failure. Secondly, in the reclassification of failure modes, a distortion failure mode is suggested, which is regarded as the fourth failure mode of engineering materials, replacing the deformation failure mode commonly used in the past. Thirdly, through introducing the concept of five elements, namely, failure mode, failure form, failure defect, failure mechanism, and failure cause, a new system of failure analysis is established, and the implant of failure form makes the system more complete. At the same time, the essential difference and relationship between failure mode and failure mechanism are elaborated. It is stressed that the failure mechanism is the key to identifying failure cause. Finally, a new expression of the relationship between failure mode and failure mechanism of metallic materials is given, revealing different failure mechanisms correspond to various failure causes.