A dustproof structure for a sleeve bearing includes an axial tube, a sleeve bearing and a dustproof cushion. The axial tube accommodates the sleeve bearing which bears an axial hole through which a shaft of a motor rotor is freely extended. The dustproof cushion is attached to an end surface of the sleeve bearing to prevent from entering foreign dust. At least one oil-returning groove is formed between the sleeve bearing and the dustproof cushion to ensure cycling lubricant so that sufficient lubricity between the sleeve bearing and the shaft is ensured.