Abstract: Structural modal parameter identification is a core algorithm in structural health monitoring system. Modal parameter identification methods have been very mature after years of development, and there are many types. The modal parameter identification method based on Hilbert-Huang Transform require researchers to subjectively select parameters in multiple steps, and cannot be directly used for long-term automatic structural monitoring. An automatic structural modal parameter identification method based on HHT is proposed. K-L divergence and DNN are used to identify and eliminate the false components generated by EMD in the first step of HHT. SSA and Butterworth filter are used to separate the aliasing modes of IMF. Hilbert transform is applied to IMF that only contains single mode information and least squares fitting is used to realize the modal parameter identification. The method is applied to a shaking table test of a three-story concrete structure, and the results show that the method can effectively and automatically identify the structural modal parameters without subjective parameter selection process.