Coal rock is a complex and inhomogeneous porous medium composed of organic matter and inorganic minerals, with strong heterogeneity. At present, few studies have considered the influence of coal rock mechanical heterogeneity on the spatiotemporal evolution of coal rock permeability and porosity. In this paper, based on the Weibull probability density distribution function to represent the heterogeneity of the elastic modulus of coal rock, a three-dimensional finite element model of thermo-fluid-solid coupling considering the pressure change, linear thermal expansion effect and shrinkage and deformation of coal rock skeleton due to methane desorption in coal is established. The permeability and porosity in coal rocks are cross-coupling correlations between temperature field, stress field and pressure field, and the variation law of permeability and porosity parameters under heterogeneity is analyzed. The results show that coal and rock mechanics heterogeneity is one of the important factors that affect the permeability and porosity distribution of coal rock. The permeability and porosity distribution of heterogeneous coal seams show obvious fluctuation and shock characteristics at different locations. Pore permeability parameters vary in size; as the distance of the borehole increases, the permeability and porosity may show the opposite trend of the homogeneous coal rock. Therefore, the evolution of porosity and permeability of coal rock is a complex process of thermal fluid-solid coupling. The results of this paper have important theoretical significance for guiding the efficient exploitation of coalbed methane.