A large number of experiments are conducted at Dunhuang national radiometric correction field every year to provide calibration services for earth-observation satellites at home and abroad. However, over several years, there are only few studies regarding the accuracy of the ground spectral sampling scheme when Dunhuang field obtains pixel-scale surface reflectance. To quantitatively evaluate the accuracy of different ground sampling schemes, the best sampling point locations were determined to obtain the surface reflectance at different pixel scales and realize high-precision and high-efficiency operational measurement of Dunhuang field. The accuracy of surface reflectance sampling methods at different pixel scales was analyzed quantitatively using Dunhuang’s high-resolution unmanned aerial vehicle data and 2 m panchromatic data from the GF-1 satellite. Based on the results, a five-point system sampling scheme is suggested to obtain pixel-scale surface reflectance from Landsat by preliminarily calibrating a 2 m quadrat within the 150 m national field in Dunhuang. For the pixel-scale resolution of meteorological satellites, the five-point-simulated annealing sampling scheme is suggested to determine the position of the 2 m quadrat in the newly selected 3 km site. In both the cases, a spectrometer is used to measure the five-point system sampling method in each 2 m quadrat.