A method of detecting a line connection of a motor is provided to quickly and accurately detect an erroneous connection between lines by monitoring the connection state in a forceful connecting process for initiating a compressor. A rectifier(110) rectifies an AC voltage to generate a DC voltage. An inverter(120) converts the DC voltage into pulse-shape three-phase AC voltages. A controller(130) receives a measurement current of the motor from a current detector and compares the measurement current with a predetermined instruction current to detect an erroneous connection in respective switching elements in the inverter. The current detector(140) is connected to a connection terminal of a BLDC(BrushLess DC) motor and the inverter. The current detector detects three-phase terminal currents from a three-phase AC voltage from the BLDC motor(150) and transmits the terminal currents to the controller.
