To study the change of bifurcation properties of the system with structural parameters,a method to find the main bifurcation parameter of the dynamic system is presented in this paper.After disturbing the eigenvalue of Frechet matrix,the main bifurcation parameter is found.Different algorithms are given for different eigenvalue forms.The bifurcation parameter which has appreciable effect on dynamic characteristics of the system can be effectively identified from multiple parameters.And the unfolding parameters can be identified as well according to the effects of parameters on the system.This method can not only be used in autonomous systems,but also in nonautonomous systems.