Surface energy distribution, CO2 flux, surface effective radiative temperature, and soil moisture over a typical steppe prairie in Inner Mongolia, China from 1 July to 〖JP2〗30 September 2007 were simulated by using Simple Biosphere model 2 (SiB2). Based on the surface flux monitoring system data, the model was initialized and driven by using short-wave solar radiation, atmospheric long-wave radiation, vapor pressure, air temperature, wind speed，and precipitation. Then the simulated and observed turbulent flux, surface effective radiative temperature, and soil moisture were compared. The results show that: 1) SiB2 overestimated net radiation, latent heat flux, and soil heat flux by 11%, 10%, and 5%, respectively, and it underestimated sensible heat flux by 6%. 2) The simulated CO2 fluxes in July and August were consistent with the observation. But the model underestimated the CO2 flux in September by 14.2%. 3) Surface effective radiative temperature was underestimated (overestimated) in the day (night). 4) Soil moisture was estimated reasonably.