Abstract: The building energy simulation software, Energyplus and Designbuilder, were employed to set up a simulation model for an airport building and the corresponding HVAC system. Based on annual onsited measured energy consumption data and FEMP (federal energy management program) standard method, an improved FEMP standard method and paired samples ttest method were introduced to verify the simulation model, the results indicate that the simulation model shows a reasonable agreement with the real system. On the basis of the verified model, the effect of supply air temperature optimal setting was simulated and analyzed to assess energy consumption for the system. It was found that decreasing the supply air temperature exhibits a favorable impact on energy saving.