A control method for an air conditioning system. The control method includes: S100, acquiring an actual cooling/heating capacity output by the air conditioning system, and acquiring an actual temperature change rate of an indoor heat exchange unit; S200, automatically learning a heat exchange load characteristic curve of the indoor heat exchange unit based on the actual cooling/heating capacity and the temperature change rate; S300, acquiring a steady state load and/or a desired load of the indoor heat exchange unit based on the heat exchange load characteristic curve; and S400 adjusting the number of operating compressors and rotational speeds of compressors, and/or adjusting the number of operating injectors and opening degrees of injectors, based on the steady state load and/or the desired load.