The invention relates to a machine set control method and system and an air conditioner. A machine set comprises at least two temperature detection modules which are mounted at different positions. The method includes the steps: acquiring a current running mode of the machine set; determining the temperature detection module corresponding to the running mode; detecting whether the determined temperature detection module is faulted or not; acquiring temperature information acquired by the rest temperature detection modules if the determined temperature detection module is faulted; transmittingthe temperature information to the machine set, and adjusting the temperature by the machine set according to the temperature information. By the technical scheme, the air conditioning system continues to normally run when the used temperature detection module is faulted, and the reliability of the machine set and user satisfaction degree are improved.