The invention relates to heating control technologies, aims to solve the problem that the existing air source heat pump hot water unit causes poor indoor temperature stability due to change of external environment temperatures, and provides a heating control system and method. According to the technical scheme, the heating control system comprises a processing unit and a temperature acquisition module and a setting module, wherein the temperature acquisition module and the setting module are connected to the processing module, and the setting module is used for a user to set an initial set temperature of a water tank according to the demand of the indoor temperature; the temperature acquisition module is used for acquiring an current external environment temperature and a current water temperature of the water tank; the processing module is used for connecting a controlled water tank. The needed indoor temperature is obtained according to the initial set temperature and the current external environment temperature, when the heating control system runs, a corresponding water tank target temperature is obtained according to current external environment processing, the water temperature in the controlled water tank is adjusted to a target temperature of the water tank, and thus the indoor temperature is kept at the needed indoor temperature. The heating control system and method has the advantages of bringing convenience to users, and the system is suitable for the air source heat pump hot water unit.