Based on radiosonde data and ERA-Interim reanalysis with resolution of 3°*3°, 2.5°*2.5°, 2°*2°, 1.5°*1.5°, 1.125°*1.125°, 1°*1°, 0.75°*0.75°, 0.5°*0.5°. The variation of 0 ℃ isotherm height in summer over High Asia during 1979-2012 is analyzed by using the climate tendency rate and linear interpolated. The relationship with latitude and altitude as well as the correlation of ERA-Interim reanalysis with different spatial resolutions and radiosonde data are discussed. The result indicates that variation of 0 ℃ isotherm height in summer since 1970s shows an increasing trend based on radiosonde data and ERA-Interim reanalysis with different spatial resolutions. 0 ℃ isotherm height based on the reanalysis data with resolution of 0.75 °* 0.75° is fluctuate between 4800~5000 m which is close to the radiosonde data. 0 ℃ isotherm height based on the ERA-Interim reanalysis with different resolutions and radiosonde data have similar spatial distribution which are usually associated with latitude and altitude. In High Asia, 0 ℃ isotherm height showed an increasing trend from north to south and from low to high elevations. ERA-Interim reanalysis with different spatial resolutions interpolated to each stations have the negative bias of most interpolated gridded data and measured data during 1979-2012, which 0 ℃ isotherm height based on the reanalysis data exists cold bias with radiosonde data, in which the small cold bias of the ERA-Interim reanalysis with high spatial resolutions and radiosonde data has a greater proportion.