Taking forest areas specified according lo information on the National digital land data, the vapour pressure deficit at leaf temperature and the degree of stomatal opening were presumed using the vegetation index of forest areas derived from Landsat TM data. Assuming the principle of Monin-Obukhov similarity is correct, a new method for calculating the latent and sensible heat fluxes of regional forests was proposed taking into account the difference in Leaf Area Index. The relation of the increase of latent heat flux with the vegetation index was obtained, and the plane distribution of latent and sensible heat fluxes in large areas is calculated.