The reliability of NCEP/NCAR reanalysis data in the climate change of Qinghai-Xizang railway line has been investigated by comparing with the observation data from 8 surface meteorological stations.The results show that the annual variation of surface air temperature and precipitation are very well presented through NCEP/NCAR reanalyzed data.The interannual variations of the air temperature at surface are quite well given from NCEP/NCAR reanalysis data.The reanalyzed temperature is more confidence than the reanalyzed precipitation.The results are better in summer than in winter and better in major part of Qinghai-Xizang railway line than at the two ends of the line.The trends of the surface air temperature analyzed by NCEP/NCAR,however,are completely different with those observed at the surface stations.The trends of the precipitation analyzed by NCEP/NCAR have been showed somehow comparable with the observation.It should be reminded that the NCEP/NCAR reanalyzed temperature values are systematically lower than the observation,but precipitation values higher than the observation.