Abstract: Based on the hard X-ray light curve data of Active Galactic Nucleus (AGNs) observed by Swift/BAT, the distribution characteristics of power law index (α) of the power spectral density of Seyfert 1s, Seyfert 2s, flat spectrum radio quasars (FSRQs) and BL Lac objects are analyzed by Fast Fourier Transform method (FFT). It is found that the index α distribution of Seyfert 2s is significantly different from that of type I AGNs (Seyfert 1s, FSRQs and BL Lac objects). The index α distribution of the subclasses of type I AGNs have no significant difference between each other. Therefore, we conclude that the hard X-rays of Seyfert 2s mainly come from the inner region of the accretion disk or Corona, and other AGN subclasses mainly come from the jet and outflowing corona. We find that the hard X-ray from the jet or outflowing corona has a larger α, while the hard X-ray from the thermal coronae of the inner region of the accretion disk has a smaller α.