The invention provides an air conditioner shutdown control method and system and an air conditioner. The air conditioner shutdown control method comprises the steps that after a shutdown instruction is received, the current operating mode of the air conditioner is obtained; and according to the current operating mode, working states of a compressor, an indoor throttle mechanism and an outdoor throttle mechanism within the preset shutdown processing time are obtained, so that a refrigerant in an indoor unit flows to piping of the compressor and/or an outdoor unit. The air conditioner shutdown control method solves the technical problem that the excessive refrigerant is accumulated on the indoor unit side during running of the super-configured indoor unit and the super long piping in the running process of the air conditioner, especially a multi-split air conditioner, and the situation that the excessive refrigerant is accumulated on the indoor unit side and thus seriously affects the refrigerant circulation requirement of a system and the refrigerant quantity required by normal running of the indoor unit is avoided.