Dynamic characteristics of surface albedo over a desert steppe ecosystem in Inner Mongolia were studied in this paper, based on the whole year′s meteorological data of 2008. The results indicated that the diurnal variation of surface albedo over the desert steppe in Inner Mongolia presented U-shape with higher values just after sunrise and before sunset, and relatively lower midday values on sunny days. Changes of soil water content resulted from rainfall would result in the decrease of surface albedo, and the influence of cloud on surface albedo was complicated. Usually, monthly mean diurnal variation of surface albedo over the desert steppe ecosystem was similar to that on sunny days with the U-shape, however, it presented V-shape in January, February, November and December. The seasonal variation of surface albedo was apparent. In growing season, surface albedo was lower because of the growth of vegetation; but during the winter, especially in January and February, it was higher. The monthly mean values in January and February were 0.56 and 0.48, respectively, and they were even larger than that of desert. The minimum monthly mean surface albedo of the desert steppe occurred in September. The value of the surface albedo was almost a constant from July to September, which was 0.236, 0.232 and 0230 respectively. In growing season, the surface albedo over the desert steppe in Inner Mongolia was higher than that over degraded grassland, agricultural land and wheat field. Only from July to October, the surface albedo over the desert steppe was obviously lower than that over the desert (the difference value was larger than 0.02). However, in other months of growing season, it was close to the surface albedo over the desert. On sunny days, the surface albedo decreased with the increase of solar altitude angle, showing a typical exponential relationship, and it almost became a constant when solar altitude angle was more than 40°. The increase of soil water content would result in the decrease of surface albedo. The linear or exponential relationship exists between surface albedo and soil water content. Thus, based on the relationship between surface albedo and solar altitude angle as well as the relationship between surface albedo and soil water content, a two-factor parameterization formula of surface albedo affected by solar altitude angle and soil water content was developed preliminarily. And this formula could explain about 68% of the variation of surface albedo. The parameterization formula could capture well the diurnal variation of surface albedo on sunny days over the desert steppe in Inner Mongolia. This formula should be validated by more representative observation data, in order to couple it into climate models or weather models. However, it is no doubt that this study could offer useful references for the precise parameterization and simulation of surface albedo in land surface model.