Quality test and reliability evaluation are prerequisites for reanalysis data to be used.To evaluate the reliability of NCEPII,ERA40 and JRA25 reanalysis data used in West China,the study analyzed the quality of the 2m temperature products.The three types of air temperature reanalysis data could well reflect the spatial distribution in West China.The difference in air temperature at stations of complex topography was relatively large while the three types of reanalysis data could provide highquality air temperature data in flat areas.Air temperature data from ERA40 and JRA25 are more reliable and can reflect more detailed air variability in large scale because they assimilate the groundbased data.Overall,the quality of ERA40 is better than the other two types of reanalysis data.