When thermal fluid was injected into a natural gas hydrate reservoir, the permeability and thermal conductivity will change as the solid hydrate saturation varied. In order to characterize the variation of physical parameters with hydrate saturation, DDF-LBM was applied to simulate the process of hydrate dissolution by thermal fluid at the pore-scale. The relaxation frequency of the flowing lattices in the pores is corrected, based on the forced conjugate heat transfer, which realized the real-time simulation of multifield coupling. The simulation results show that, the hydrate dissolution rates of two different structures are essentially same. Based on the above results, we obtained the exponential fitting equations between different hydrate saturations and average permeability, effective thermal conductivity. The fitting results show that, the correlation between saturation and relative permeability and effective thermal conductivity were negative. The simulation results can provide important reference for describing the heat and mass transfer laws of natural gas hydrates mining with thermal fluid injection.