In this paper, a general model of rotor support misalignment fault is proposed. The equivalent coupling model parameters are calculated by using the radial stiffness and angular stiffness of the coupling, and the mechanical model of the coupling is established which has left and right half couplings and multiple connecting pairs connected to each other. The total radial stiffness and angular stiffness of the equivalent coupling are equivalent to the actual coupling. And the model parameters of the equivalent coupling are calculated according to the stiffness of the actual coupling. Then the stiffness difference and the nonlinear stiffness problem, the excitation force model of the angle misalignment fault of the coupling is established according to the uneven distribution of the circumferential position of the connection pair. In addition, the rotor-support coupling dynamic model with the rotor bearing misalignment fault is established. The vibration response characteristics of the rotor under the misalignment fault are analyzed by numerical simulation. The generation mechanism of characteristic frequency of misalignment fault is revealed. Finally，the test of rotor support misalignment fault under various misalignment conditions at characteristic speed is completed. And the test results verify the correctness of the rotor support misalignment fault model proposed in this paper.