[Objective]to investigate the clinical effect of Knotless suture in primary total hip arthroplasty (THA).[Methods]Retrospective analysis from 2017 November to 2019 April, 72 cases who had undergone primary unilateral THA through posterolateral approach were included in this comparative study. According to the different methods of incision suture, the patients were randomized into continuous suture group and conventional interrupted suture group.Two groups use the same surgical technique and perioperative management.Suture time, postoperative drainage volume, time to a dry wound, infection rate and other complications of the two groups were compared, and hip function (Harris score) and pain (VAS score) of the two groups were also evaluated and compared.[Results]Closure time and time to a dry wound in the continuous suture group [（12.25±1.27）min，（3.88±0.56）d] were superior than that conventional interrupted suture group [（20.44±1.56）min，（5.36±0.38）d] with significant differences ( P < 0.01 ). There was no significant difference in Postoperative drainage volume between the continuous suture group and the conventional interrupted suture group (P > 0.05).There was no statistically significant difference between the two groups in Harris scores of hip function and VAS scores of pain (P > 0.05). [Conclusion]when the incision is closed for total hip arthroplasty, the knotless continuous suture can reduce the intraoperative suture time and time to a dry wound without increasing postoperative incision drainage and affecting hip joint function and pain.