The full air conditioning and the stratified air conditioning designs in large space buildings were investigated based on air flow measurement that pertains to an in-patient hall of a hospital building. We compared and analyzed the indoor comfort parameters such as temperature and air velocity. On the basis of the measurements, we calculated the theoretical load index by solving the model for inner surface temperature of the building envelope based on the modified radiant heat transfer method. Using flow fields and parameters that are generated by computational fluid dynamics (CFD), the indoor thermal comfort when adopting the full air conditioning and the stratified air conditioning designs can be effectively analyzed. And the respective energy saving rate of the two air conditioning design loads in the hall at different storey heights, window-wall ratios, and air supply heights can be compared. Finally, the recommendation for usage of the stratified air conditioning design was put forward in large space buildings.