Selecting a good site for ground-based astronomy is very important.Based on the ERA-Interim global reanalysis data,this paper studied the atmospheric conditions of the Qitai Telescope(QTT)site from the aspects of absolute humidity,mixing ratio and precipitable water vapor(PWV).Error estimations of meteorological parameters are also analyzed.These primary results show that the QTT site has obvious advantages in terms of conditions with much less atmospheric water vapor than two well-known existing sites with 100-meter-aperture radio telescopes in the world.In addition,due to the influence of atmospheric water vapor on radio observations,the atmospheric transmittances for each frequency band of the site are simulated,and the atmospheric opacity is also calculated as well as Planck radiation brightness.Based on these results,the effective observational time of different bands is further estimated.