Abstract: Measurements both from eddy correlation system and evaporation pan are used to derive aerodynamic resistance over bare soil surface as well as maize field. Diurnal variations of aerodynamic resistance are also analyzed. A comparison is made between the aerodynamic resistances derived from the two observation methods. Results show that the diurnal variation of aerodynamic resistance during daytime is obvious for both bare soil surface and maize field although the variation range is limited (0—200 s/m). Aerodynamic resistance derived from measurements by evaporation pan is normally smaller than that by eddy correlation system.