Disclosed are an operation control device of a compressor, which can reduce motor loss by applying an AC power to a motor of the compressor without a switching operation of a control unit, and a method thereof. The operation control device of the compressor comprises: a capacitor electrically connected to a motor of the compressor and having a predetermined capacitance; a control unit connected in series to the motor of the compressor and applying an AC power to the motor of the compressor according to a control signal; and a controller detecting a load variation amount on the basis of a current and voltage applied to the motor of the compressor and controlling on/off of the control unit according to the detected load variation amount.