Based on the global 1°×1° and 3-hr atmospheric forcing data from 1948 to 2006 developed at Princeton University,the global land surface conditions in recent 50 years are produced by offline simulation with three different versions of NCAR Community Land Model(i.e.,CLM3.0,CLM3.5 and CLM4.0).Through comparing the simulation results,the differences in simulated soil temperature,soil moisture,latent heat,sensible heat and surface runoff among the three models and the main features are discussed.Results show:1)Differences in the simulated soil temperature and soil moisture are detected among three versions of CLM.Compared to CLM4.0,both CLM3.0 and CLM3.5 show warm bias in the simulated January and July soil temperatures at both shallow and deep layers in the mid-high latitudes of the Northern Hemisphere.The soil moisture simulated by CLM3.0 is too wet in the high latitudes of the Northern Hemisphere,but too dry in the mid-latitudes and the tropics.In contrast,no evident difference is found between CLM3.5 and CLM4.0 except that the soil moisture at shallow layer simulated by CLM3.5 is wetter than that of CLM4.0 in the high latitudes of the Northern Hemisphere.2)Evident differences in the simulated surface energy fluxes and hydrological variables are found among three versions of CLM.Compared to CLM4.0,the differences in the latent heat and sensible heat fluxes simulated by other two models mainly appear in the Tropics.CLM3.0 underestimates(overestimates) the latent heat(sensible heat) fluxes to some extent,while CLM3.5 basically gives larger latent heat flux(smaller sensible heat flux).In addition,the surface runoff simulated by CLM3.0 is evidently overestimated in the tropics,where it is improved but somewhat underestimated by CLM3.5.3)Differences among the model results vary with not only the season but also the selected region.On the whole,CLM3.0 produces larger bias in the simulation of the seasonal cycles of the soil moisture and canopy transpiration over the selected regions,and underestimates the soil moisture and the contribution of canopy transpiration to canopy evapo-transpiration seriously.Such results have been improved in both CLM3.5 and CLM4.0.In case of other land surface variables,CLM3.0 also exhibits some deficiencies,but CLM3.5 and CLM4.0 show better performance.