Many physicians perform traditional Acromioplasty (AMP) in arthroscopic Rotator Cuff Repair (RCR) surgery. However, this surgery might cause shoulder pain, or joint instability postoperation. We compared the clinical efficacies of Arthroscopic Subacromial Smooth Polishing (ASSP) and AMP in RCR. The clinical data of 74 patients performed ARCR were retrospectively analysed, among who 36 patients were performed intraoperative SSP, and 38 patients were performed traditional AMP. The clinical efficacies of the two groups were compared, evaluated, and statistically analysed using VAS, Constant-Murley shoulder Score (CMS), and MRI before the surgery (T1), 3 months after the surgery (T2), and in the last follow-up (T3). The patients were followed up 18-36 months (average 26.9 months). The postoperative VAS and CMS of the two groups were statistically significantly different from those at T1 (P<0.001). The comparison of VAS and CMS between the two groups at T2 and T3 showed statistically significant differences (P<0.001), but the rotator cuff healing time showed no significant difference (P>0.05). SSP can significantly reduce postoperative shoulder pain and improve joint functions than AMP, but it cannot shorten the rotator cuff healing time.