A motor controller for an air-conditioner fan, including at least a central processor, a power drive module, a power supply module, and a communication interface circuit. The power supply module supply working power to the central processor and the power drive module. Multiple instruction input ports are connected to the central processor. Multiple parameters N are set in the central processor and corresponding to the instruction input ports. The central processor controls the power drive module to drive a motor of the air-conditioner fan to operate at a parameter N corresponding to an instruction input port as the instruction input port is connected. The communication interface circuit is communicated with an external communication device. The external communication device changes the parameters N in the central processor corresponding to the instruction input ports via the communication interface circuit.