The complex resistivity parameter was obtained based on the measured impedance spectroscopy of the methane hydrate-porous medium-brine of 3.5%. The frequency dispersion characteristics of complex resistivity and the effects of hydrate saturation were analyzed. Finally a model of complex resistivity was proposed for hydrate saturation estimation. It has been demonstrated that the complex resistivity of porous medium containing methane hydrate exhibits remarkable frequency dispersion characteristics within the range of 0.1 Hz~1 MHz. There is a close relationship between the methane hydrate saturation and characteristic parameters of frequency dispersion. The frequency dispersion characteristics of complex resistivity becomes more significant with the decrease of hydrate saturation. The amplitude, real part and imaginary part of complex resistivity vary linearly with the test frequency in the double logarithmic coordinate within the range of 0.1Hz~10Hz, and there is a nearly linear relationship between the absolute values of slope and hydrate saturation. The percent frequency effect of the amplitude and real part of complex resistivity decreases linearly with an increasing hydrate saturation within the range of 10 Hz~1 MHz. Under the test conditions in this study the impedance spectroscopy of porous medium containing hydrate can be fitted through an equivalent circuit model with a resistor and capacitor in series, and the resultant complex resistivity model can be used to calculate the gas hydrate saturation.