This paper firstly conducted push-out test and dynamic signal test on CFST. The difference of nonlinear vibration characteristics of CFST in different working conditions in push-out test was analyzed. And the influence factors of nonlinear characteristics of CFST were studied. The first order of vibration signal was extracted by utilizing analytical mode, the relationship of frequency-amplitude was obtained by Hilbert transform. The test results of three CFST members show that the nonlinear vibration characteristics first increase then decrease in all loading process, and the characteristics are affected by the interaction between steel tubular and concrete. The interface of cementation is weaken by the poor quality of concrete placement, thus the nonlinear characteristics is relatively low when the concrete debonding isn't occurred.