Purpose. Previous studies have demonstrated pronounced reduction of sleep quality following major surgery, which may affect postoperative pain and early recovery. This prospective, randomized, controlled trial was designed to evaluate the effect of zolpidem on sleep quality in fast-track total knee arthroplasty (TKA). Methods. 180 patients who underwent primary TKA were enrolled in this study and randomized 1:1 to receive either zolpidem (Group A) or placebo (Group B) for 6 days. VAS pain scores (rest, ambulation, flexion, and night), range of motion (ROM), opioid analgesics use, postoperative nausea and vomiting (PONV) and other complication, sleep efficacy and patients VAS satisfaction were recorded postoperatively and at 1, 3, 5 after surgery. Sleep quality was measured using the polysomnography (PSG) and Epworth Sleepiness Scale. Results. Sleep efficiency was decreased on all three postoperative nights but returned to pre-admission levels on the fifth postoperative night in Group A. Compared to Group B, Group A showed better sleep quality in early period. It was found that patients taking zolpidem showed greater improvement in quality of life, better patient VAS satisfaction, lower pain VAS score, and less opioid analgesics use. Conclusion. In conclusion, sleep quality is impaired after total knee arthroplasty and zolpidem could improve postoperative sleep or pain and be beneficial to patients' post-TKA early recovery