Aiming at the poor ability of wear-resistance and corrosion-resistance of sucker rod couplings, surface ultrasonic nano-crystallization treatment of sucker rod couplings was studied. The roughness, hardness, corrosion-resistance and wear-resistance of the coupling after surface ultrasonic nano-crystallization treatment were evaluated by experiments. The results indicated that corrosion-resistance and wear-resistance of the couplings after that kind of treatment is fine and it also can solve the problem of the wear-resistance of tube. The life of sucker rod and tube can be prolonged effectively.