The empirical mode decomposition has many defects in the mechanical signal processing, so the method of variational mode decomposition is focused on and introduced, and referred it to mechanical signal processing. Firstly, the variational modal decomposition was applied to the vibration signal, a set of modalities would be obtained, then the sensitive modality related to the fault would be screened, and finally the envelope power spectrum analysis would be performed. The simulation signal and the actual rolling bearing signal are used to test the effectiveness of the method, which finally proves that the variational modal decomposition method can accurately detect the rolling bearing fault.