Abstract: Based on the partial continuous waveform data of Zhongxiang station in 2018, the non-stationary property of the ambient noise is studied by using the Detrended Fluctuation Analysis method (DFA) including the pure ground motion noise and the ground motion noise during earthquake. This paper focuses on studying the variation relations of scaling index of the three component of seismometer. The results show that the noise has long-range coherence when there is no earthquake, which is reflected by the similarity inside the sequence, the ground motion noise is suppressed when earthquake occurs, and the horizontal scale index value is significantly higher than that in the vertical direction, which may be related to the orientation of the earthquake.