Abstract: To study the mechanism of losing stability, the nonlinear submarine maneuvering motion model in dive plane was established. The bifurcation and catastrophe theory methodology was adopted to analyze the motion stability. The motion equations of submarine were reduced to a lower system which contains all dynamic properties of the original system by utilizing center manifold theory. The status catastrophe caused by static bifurcation and dynamic bifurcation was respectively discussed. The numerical simulation results in MATLAB/Simulink program showed that the transcritical bifurcation or Hopf bifurcation occurred in submarine operating motion with high-speed and large rudder angle in dive plane. And bifurcations would lead to status catastrophe at bifurcation points. These catastrophe phenomena reveal the effect of nonlinear terms in submarine dynamic model, and provide necessary theoretical basis for submarine maneuvering control system designing.