Usinga new methodand theturbulence observation data from Maqu station, the surface roughness length during soil freezingand thawing season over Eastern Qinghai\|Xizang Plateau was estimated. The main results show that the method used in this paper is feasible to determine surface roughness length. Surface roughness length during soil freezingand thawing season has a little decrease trend. The surface roughness length of three phasein the season, unfrozen time, frozen time and melted time, are 3.23 10-3m， 2.27×10-3m and 1.92×10-3m, respectively. The contrastwithother place shows that the surface roughnesslengths indifferent places overQinghai\|Xizang Plateau havegreater difference.