1. A method for constructing component fault tree based on physics of failure, comprising: establishing, based on common characteristics of component physics of failure and according to six layers based on physics of failure and category of the component, a fault information database containing information of the six layers based on physics of failure; constructing, based on the fault information database and according to the six layers based on physics of failure and logical relationship of physics of failure, a component fault tree of n levels of events of six layers based on physics of failure, wherein n is greater than or equal to 6; and simplifying the fault tree by means of failure mechanism sub-tree transferring and fault module sub-tree importing.