The invention relates to a motor assembly and bearing sleeve thereof; wherein the motor assembly comprises a gear box (1) and a motor (2), the output shaft of the motor penetrates a bearing assembly, the bearing assembly is arranged between the end cap (21) of the motor and worm (25) and is contained in the cavity (12) of the gear box (1), the bearing assembly comprises a bearing (3) and a bearing sleeve (4), the inner ring surface of the bearing (3) supports an output shaft (22), and the outer ring surface is provided with a plurality of axial anti-rolling edges (31); the inner ring surface of the bearing sleeve (4) is provided with a plurality of axial joint grooves (41) to mesh the anti-rolling edge (31) of the bearing, and the outer ring surface is fixed on the inner wall of the cavity (12); and one end of the bearing assembly is close to the bottom of the cavity, and the other end is close to the end cap, so as to prevent the bearing assembly from moving along axial direction. The invention can reduce vibration of output shaft of motor under rated load, improves axial strength, avoids axial bending and improves self-locking capability of motor.