Abstract: The experimental data of CH4 adsorption on coals and shales are fitted by using Freundlich empirical formula, Langmuir model, extended Langmuir model, Toth adsorption model and Langmuir-Freundlich adsorption model. The fitting degrees is also examined. The results show that both the coal and the shale, the fitting precision of three?parameter model is higher than that of two?parameter model. For the two?parameter models, the fitting degrees of Langmuir model on coal and shale is much higher than the Freundlich empirical formula model by more than 8 times. For the three?parameter models, their fitting degrees are all higher, of which Toth model is the highest in fitting degree than E?F and L?F models at an averge temperature for shales, but for coals, it is lower than the other two. On the whole, Toth model and L?F model are better for fitting of coals and shales rather than Freundlich empirical formula. The study results are of guiding significance in proper selection of isothermal adsorption model for coals and shales