[Objective] The applicability of six multi-source gridded soil moisture datasets was evaluated, in order to provide scientific precision information of soil moisture and selection basis for land-atmosphere coupling study, drought monitoring and land water resources monitoring under the background of climate change in Inner Mongolia Autonomous Region.[Methods] Using the soil moisture data observed by 63 meteorological stations in every ten days at 0-10 cm level from May to September from 2016 to 2020 in Inner Mongolia Autonomous Region, and taking correlation coefficient, mean absolute error and root mean square error as evaluation indexes, the accuracy and spatio-temporal variation of the SMAP soil moisture from NASA, ESA CCI from the European Space Agency(ESA), CLDAS from the China Meteorological Administration(CMA), ERA5 and ERA5 Land from the European Centre for Medium-Range Weather Forecasts(ECMWF) and NOAH from the global land surface data assimilation system(GLDAS/NASA) were systematically evaluated.[Results] ① Six gridded soil moisture datasets could truly reflected the spatial distribution characteristics of soil moisture in Inner Mongolia, and SMAP was the best. ② According to the statistical characteristics of the time series of soil moisture in Inner Mongolia Autonomous Region and its three climatic regions, the six gridded soil moisture datasets better reflected the temporal variation trend of soil moisture. SMAP was the closest to the measured data, and the other five datasets were generally higher in semi-humid and semi-arid regions of Inner Mongolia, and ERA5 and ERA5Land overestimated higher. In arid regions of Inner Mongolia, SMAP, ERA5 and ERA5Land were closer to the observations. ③ Six gridded soil moisture datasets in Inner Mongolia and its three sub-regions had very significant correlation coefficients, and the correlation coefficients between SMAP, ESA, CLDAS, ERA5, ERA5Land and the observed data was obviously better than that of NOAH. The mean absolute error and root mean square error of SMAP data are significantly smaller than those of the other five datasets.[Conclusion] Six gridded soil moisture datasets have different applicability in Inner Mongolia area. The quality and applicability of SMAP soil moisture are the best, ESA is the second, NOAH is the worst.