The invention discloses a DC brushless motor which comprises a rotor assembly. The rotor assembly comprises a rotating shaft and iron core sheets, the iron core sheets are axially mounted on the rotating shaft, the axial end of the iron core sheets includes groups of insert holes in axial distribution, and magnetic steel is embedded into the insert holes. The DC brushless motor is convenient to assemble, the problem of magnetic field weakening due to arrangement of a stainless steel ring is solved, and the power of the DC brushless motor is improved.