Based on the Relation of Evolution among Systems to Analyze Brittleness of Complex System

The qualitative description and the subsystems important degree of complex system are given. It is the basic of the later research of this paper. As complex system itself is of strong coupling characteristic, hierarchy characteristic and so on, it is difficult to study brittleness, which is one new properties of complex system. It is not easy to set up catastrophe potential function by using conventional means and to choose control variables of catastrophe potential function. On the basis of that, the method of setting up potential function is given to analyze the brittleness of complex system by means of relation of evolution among systems. In conclusion, the method is presented in this paper is of simplicity, easy and value of practical applications.