The observation data collected by Atmospheric and Environmental Comprehensive Observation and Research Station on Mt. Qomolangma, Chinese Academy of Sciences (AECORSQ,CAS) and the AIRS(Atmospheric Infrared Sounder) satellite data obtained during the period of from March to May of 2008 are employed to analyze the diurnal changes and the vertical features of atmosphere over the northern region of the Himalayas in spring. The results show that the diurnal mean variation of surface air temperature has one-peak-one-vale pattern. The highest temperature  occurred around 18:00  Beijing  local time and the lowest was between 7:00 to 9:00 Beijing local time.The diurnal mean variation of wind speed has onepeak pattern, and the air pressure has two-peaks-two-vales pattern while the lowest occurred at 19:00 Beijing local time. The diurnal mean variations of sensible heat flux and latent heat flux were consistent with the diurnal change of air temperature. The pattern looks like the net radiation diurnal pattern, but the peak time appears about 2 hours later. The sensible heating flux is stronger than latent heating flux over the Tibetan Plateau in spring. There are two main reasons which caused the remarkable diurnal variation of air temperature over the Tibetan Plateau while the mass of the atmosphere over the plateau is much less than the mass of atmosphere over other regions, and it can gain more solar shortwave radiation and less shortwave radiation while the optical depth over this region is smaller.