The invention teaches a brushless DC motor, comprising a brushless DC motor unit and a controller unit, wherein the brushless DC motor unit comprises a stator assembly, a permanent magnet rotor assembly magnetically coupled with the stator assembly, an enclosure supporting the installation of stator assembly and the permanent magnet rotator assembly, an end shield installed at the end of the enclosure, the rotating shaft of the permanent magnet rotor assembly projecting out of the end shield; the controller unit comprises an integrated power module, a microprocessor unit, a rotor position sensing circuit, a power source circuit, an I/O interface circuit, a current-sensing circuit, and a controller box; and the controller unit is electrically connected to the brushless DC motor unit. The brushless DC motor of the invention has an ideal control circuit with a plurality of control units serving to control the motor operation characteristics stored in the microprocessor unit so that the brushless DC motor is broadly universal and can be operated under a plurality of control modes.