The 32year mean (1971-2002) NCEP/NCAR reanalysis monthly data are investigated by comparing with temperature and geopotential height data obtained from radiosonde reports of 12 stations over the Tibetan Plateau. The main conclusions are as follows: 1) Monthly temperature and geopotential height of the reanalysis data are almost consistent with the observation data in climatology, the reanalysis data can objectively represent the climatic characteristics of the Tibetan Plateau. 2) There are strong positive correlations between reanalysis data and observation data over the Plateau, the interannual variations of temperature and geopotential height from the NCEP/NCAR data are closer to the observation data. 3) There exists a declining trend of temperature and geopotential height at upper troposphere and stratosphere analyzed by NCEP/NCAR reanalysis data. The reanalysis data have been showed somehow comparable with the observation data since 1979, but the geopotential height and temperatures at lower troposphere from NCEP/NCAR reanalysis do not agree well with the observations by reason that there exist some uncertainties in studying the interdecadal trend in the reanalyzed data. From the above results, it is suggested that the monthly mean temperature and geopotential height estimated from NCEP/NCAR can be applied into climatic research of the Tibet. The reanalyzed data is better after 1979 than that before, especially in stratosphere.