Abstract: In order to study the physical mechanism of frequency dispersion of complex resistivity of coal at 0-200 kHz, the amplitude-frequency and phase-frequency of complex resistivity of coal are measured under variable frequency of constant current. Using the Fourier inverse transform to convert the frequency domain data of complex resistivity of coal into time domain data; Using the Cole-Cole model, the complex resistivity dispersion data are fitted; Drawing on the electric double layer deformation hypothesis theory, the dispersion mechanism of complex resistivity of coal is studied by comparing the frequency dispersion of sandstone. The results show that in the current frequency range of 0-200 kHz, the measured dispersion characteristics of the complex resistivity of coal mainly reflect the induced polarization effect of coal and are interfered by electromagnetic induction. The complex resistivity of coal has dispersion characteristics, and the cause of dispersion is mainly caused by induced polarization, and the degree of influence of electromagnetic induction is small. It is theoretically feasible to develop a new method for coalfield exploration and logging based on the complex resistivity dispersion characteristics of coal.