With the economic development and urbanization in China, the demand on improvement of indoor thermal environment has been increasing rapidly. Regarding the impact of Indoor setting temperature on energy consumption of heating and cooling, DeST-h is adopted for the investigation of some operation modes for some selected cities in different climate zones. It is found that 40%~60% reduction could be obtained with appropriate modes change. And non-heating-and-cooling period could be extend with appropriate indoor temperature setting, which could be found 7% reduction in energy consumption for 1 ℃ change.