A controller of an air-conditioning unit, and an air-conditioner. The air-conditioning unit uses a power line carrier communication (PLC) to communicate. The air-conditioning unit includes multiple air-conditioner indoor units and multiple air-conditioner outdoor units. The operation of the air-conditioning unit is controlled by a controller. The controller includes: a plug component configured to be plugged into a socket in a preset PLC communication network and a controller body component connected to the plug component and configured to receive a communication signal from a target device and transmit the communication signal to a device matching the target device, the target device including one of an air-conditioner indoor unit and an air-conditioner outdoor unit.