Abstract: Based on the data obtained from the observation of the wind speed gradient and temperature gradient during the period of the plateau's meteorological experiment from May to August in 1979, and by using Kichardson number R₁, the atmospheric stratification stability condition of the plateau's boundaty layer has been analysed in this paper, It shows, the R; number of the plateau is smaller than that of the plain on daytime but at night the former is larger and their difference is very obvous.The vate of R; number between the plateau and the plain.May reach 5-10 times, so the relative effect of the thermal factor on the rule of turbulent motion of the plateau's boundary layer is larger than that of the plain's.The paper also shows, the relative increase of thermal action is resulted from the decrease of dynamical factor (the wind gradient) and it isn't resulted from the increase of the temperature gradient.Based on some data of references, the mean relation between R; number and a_T(a_T=K_T/K), there K_T and K are thermal turbulent exchange coefficentand moment turbulent coefficent respectively) has been got too.It approaches to 1.in the plain, but on the plateau it doesn't.This fact shows, the Model of K_T≈K calculating the surface sensible heat flux which is often used in plain can't be used on the plateau.This is an important problem in the study of the plateau surface heat balance.