Objective To observe the efficacy and safety of oxycontin treatment in cancer patients with mod-erate to severe chronic cancer pain.Methods This study was performed by study group and control groups.120 cases of patients with moderate to severe chronic pain were enrolled in study group and treated with oxycontin(10mg/time, once every 12 hours).50 cases of patients with moderate to severe chronic pain were randomly allocated to control group and treated with tramadol hydrochloride sustained-release tablets(100mg/time,once every 12 hours).Clinical efficacy and adverse reactions of patients in the study group and control group were evaluated after therapy for three weeks.Results There was 35 cases of complete remission,80 cases of partial remission,and 5 cases of mild remis-sion,and the overall response rate was 95 .8% in the study group.In addition,there was 4 cases of complete remis-sion,4 0 cases of partial remission,4 cases of mild remission and 2 cases of no effect,and the overall response rate was 88.0%,there was statistically significant difference(P=0.004).Meanwhile,the rates of adverse reactions in the study group and the control group were 16.7% and 14.0%,respectively,there was no statistically significant differ-ence(χ2 =0.188,P>0.05 ).Conclusion Oxycontin can effectively safely treat cancer patients with moderate to severe chronic pain.