The invention provides a comprehensive assessing method for security threat situations in an electric cyber physical system, and the method is performed through the following steps: building a comprehensive situation assessing index system for an electric cyber physical system based on an analytic hierarchy process; carrying out detection and statistics to events that pose security threats to the system and obtaining the real time detection statistics on the events; computing for comprehensive assessing values for the security threat situations; and warning in real time high level dangerous security threats based on the comprehensive assessing values for the security threat situations; According to the invention, for the first time, through a macroscopic perspective to display the security situation of an ECPS, the mapping relation between the input and the output of the comprehensive assessing of an ECPS security threat situation and the impact of such relation to the ECPS security and stability are defined so as to raise the security and protection of the ECPS. With such a method, it is possible to effectively administrate security protection to high level dangerous security threats, therefore improving ECPS running conditions generally and ensuring the system operates in safe.