This will be an open, prospective, parallel-group, randomized controlled trial. Patients scheduled for complex anorectal surgery under general anesthesia will be enrolled, and the perioperative analgesia mode led by anesthesiologists will be established. Compared with the perioperative analgesia mode led by surgeons, the efficacy and safety of analgesia, quality of life and satisfaction of patients will be evaluated. This study is aimed at the feasibility and efficiacy of anesthesiologist-led treatment mode in the management of moderate and severe pain in patients after complex anorectal surgery.