Based on the 24 h hourly outdoor temperature forecasts from Beijing Rapid Update Cycle （BJ RUC）NWP and observed indoor temperature from Beijing Haiyuan Community during 1-15 March 2010, the relations between heat supply and loss， indoor and outdoor temperature, supply and return water temperature of heating system for buildings are established by using the principle of the energy equilibrium. A numerical simulation model of supply and return water temperature is deduced. The simulation experiment of hourly temperature forecast is carried out. Then the simulated forecast is compared to the observed temperature in Beijing Haiyuan Community. The results show that the mean square root error between simulated indoor temperature and required temperature (20℃) is 0.25℃. Comparably, the actual error of operation in Beijing Haiyuan Community is 1.53℃. The root mean square errors between simulated and observed supply water temperature and return water temperature are 3.69℃ and 3.80℃ respectively. Which is much less than the actual operation error 1.53℃ in Beijing Haiyuan Community.