In active magnetic bearing (AMB), the beat vibration will affect the flywheel rotary precision. A vibration model, which includes general dynamic stiffness and unbalance response different from the existing vibration research, is proposed to analyze the vibration characteristics, and the vibration model can express the actual system vibration features from the mechanism. In order to solve the vibration model, it is considered as a multi-degree-of-freedom vibration system. Both the free vibration and the forced vibration are analyzed according to the proposed model's solution, and therefore the beating vibration is discovered when the two vibration frequencies are similar. The weakening measures of the unbalance vibration and the beat vibration are also discussed by analyzing the general dynamic stiffness changing. The simulation and experimental results demonstrate the validity of the theoretical analysis. The vibration analysis results can provide effective mechanism support for active magnetic bearings vibration characteristics research, and the vibration model can provide simulation platform for others applied Research.