This invention relates to a torque control device and a method for DC frequency conversion compressors including a current sampling part and a control part, in which, an 180deg. sine wave DC conversion mode is applied to test the position of a compressor rotor timely and control is carried out by the applied drive voltage to the motor of the drive compressor so as to adjust the output torque of the compressor timely and the compressor can keep torque balance at any time in the process of operation.