Abstract: Objective : To observe the analgesic effect and adverse effects of Oxycontin (Oxycodone HydrochlorideControlled- release Tablets) on moderate and severe chronic cancer pain. Methods : A total of 50 patients withmoderate and severe chronic cancer pain were selected. There were 26 males and 24 females, with an average age of 54.21±12.26 years, and they had no major complications, liver or kidney damage or history of drugabuse. The most common type of pain was bone pain. Other types of pain included chest pain, abdominalpain, nerve pain and hip sacral pain. The dosage of Oxycodone Hydrochloride Controlled- release Tabletswas 10 mg, administered when the patients complained of pain. It was the first time for all of the patients totake Oxycodone Hydrochloride Controlled-release Tablets. This medicine must be swallowed whole and wasnot to be separated, chewed or ground. Oxycodone Hydrochloride Controlled-release Tablets were administered at an initial dose of 10 mg every 12 hours and the dose was increased to achieve pain relief. If the painwas decreased less than one grade after 24 hours, the dosage was increased to 20 mg·12 h^-1 the next day.If the pain was still decreased less than one grade, the dosage on the third day was increased to 30 mg·12h^-1. The maximum dosage was 60 mg·12 h^-1. All patients received this therapy for 4 weeks. Results : The doses ranged between 10 mg·12 h^-1 and 60 mg·12h^-1. Among the 50 patients suffering moderate and severechronic cancer pain, 19 (38.0%) achieved complete remission, 29 (58.0%) achieved partial remission, and 2(4.0%) achieved minor remission. Pain relief provided by Oxycodone Hydrochloride Controlled-releaseTablets was 100% (7/7) in patients with moderate chronic cancer pain, 95.3% (41/43) in patients with severechronic cancer pain, and 96.0% (48/50) for all patients combined. The adverse reactions were constipation (9cases), nausea and vomiting (6 cases), abdominal distention (3 cases), anorexy (2 cases), lethargy (2 cases)and dizziness (1 case). Conclusion : Oxycodone Hydrochloride Controlled-release Tablets are safe and effective for moderate and severe chronic cancer pain. They work quickly with few side effects.