There is great energy saving space for buildings of colleges and universities. The heating energy consumption simulation was made using the software TRANSYS-17 for a teaching building of one college in Beijing. The energy saving rate of its heating energy saving reconstruction plan was calculated and the room temperature of two successive heating period were measured and compared. From simulation results, we can found that the heating energy saving amount is 351765282 kJ and the energy saving rate is 19.78% after adding exterior wall insulation. From room temperature measurement, we can found that the room temperature increase 1~3℃ after adding exterior wall insulation when outdoor temperature are basically the same. If the time control heating can be further made in this teaching building, that is to say in the daytime (7：00~22：00) the heating temperature is set at 16~18℃, in the nighttime (22：00~7：00) and in winter holiday it is set at 5℃, the heating energy saving amount will be up to 614256842 kJ and the energy saving rate will be up to 34.55%.