We performed molecular dynamics (MD) simulations to study structure, stability, and dynamics of the water adsorption layer on muscovite mica at several temperatures (from 298 K to 673 K) and pressures (0.1 MPa, 10 MPa, and 50 MPa). We studied the structure of the adsorption layers with three characteristic peaks of density and orientation of H2O molecules in one-dimensional and two-dimensional profiles. The results show that the water adsorption layers become less structured and more mobile as the temperature increases. We also found the first and the second layers are less diffusive than the third one, and the difference of diffusivity gets unclear as the temperature increases. Finally, we discuss implications to hydration forces and wettability, which are significant interfacial properties of the multiphase fluids system such as water/gas/mineral systems, from the viewpoint of water adsorption film with nanometer thickness.