Objective. This study was conducted to compare postoperative pain and functional recovery in bilateral unicompartmental knee arthroplasty (UKA) and unilateral UKA after cocktail therapy. Methods. A total of 240 patients who received unilateral UKA and bilateral UKA in our orthopedic department from February 2019 to April 2020 were collected. The general clinical data was recorded and compared between the two groups of subjects, and the time of postoperative landing was recorded separately for both groups. A visual analogue scale (VAS) was used to record the patients’ pain at 1, 7, and 14 days postoperatively, as well as the range of motion of the affected limb at 1, 7, 14 days, and 3 months postoperatively and the hospital for special surgery (HSS) knee score of the knee at 1 month postoperatively. Results. After cocktail injection analgesia, unilateral patients with knee surgery got off the ground and walked significantly earlier than patients with bilateral surgery, while there was no significant difference between the two groups in terms of pain at 1, 7, and 14 days after surgery, range of motion of the affected limb at 1, 7, 14 days, and 3 months after surgery, and knee HSS score at 1 month after surgery. Conclusion. Periarticular cocktail injection significantly reduces postoperative pain in patients, and bilateral UKA surgery can be used as satisfactory as unilateral UKA in clinical practice.