Abstract: Commercial buildings are effective resources to provide load shedding and shifting on timescales of seconds to minutes. In order to get them to participate in power balance, it is important to estimate their aggregated demand response potential. For this purpose, this paper modeled the thermal dynamics of buildings by using EnergyPlus, and proposed an estimation method under the control strategy of change HVAC system temperature setpoint. Furthermore, regression models are fit to reduce the complexity of computation, which can describe the relationship between response potential and the outside air temperature among different periods. Simulation results show that commercial buildings have huge potential, besides, linear regression fitting is valid and a more easy way to calculate potential of commercial buildings.