Aiming at the nonlinear dynamic characteristics of rudder structure system, typical vibration me-chanic models for rudder structure system with dry friction and clearance are established. Theoretical analysis method is used to study the mechanism and rules of the typical nonlinear dynamic phenomenon for rudder structure system, i.e., variable stiffness、amplitude skipping、self-excited vibration and low frequency phase lag abnormal increase. The theoretical analysis results are compared with numerical and test results, good consistency is showed and the models along with the analysis methods established are rational.