Heat supplies not only consume large amounts of energy, but also are very inefficient. However, in this case, a monitored control system which will realize 10% energy conservation in heat supplying is designed. This system has a two layer structure: one on-spot control layer and one upper supervisory layer. The former is exploited by PLC; the latter supervise and control the former via GPRS wireless communications. The Internet network will also in this system monitor any of the substations far away from the controlling centre. In this paper, the control scheme, hardware and software of the system will be introduced in detail. Until now, the system has been steadily running for more than 2 heating periods in the station and has pass all the relevant departments’ technical tests.