Objective To evaluate effect and adverse effect of oxycontin and MS contin in the treatment of sever cancerous pain.Methods 204 patients with sever cancerous pain were randomly derided into 2 groups,oxycontin and MS contin group.Each pain was evaluated in every 48 hours and dose was adjusted according to the pain relief.And 2 groups were evaluated the analgesic onset time,effect and adverse effect,respectively.Results Efficiency was according to less than or equal to 3 of pain score after administer in analgesic effect.Effect rates of oxycontin group and MS contin group were 79.4 ％ (81/102) and 75.5 ％ (77/102) respectively,and the difference was not statistically significant (x2 =0.225,P ＞ 0.05).However,there were significant differences in the analgesic onset time between two groups (x2 =22.916,P ＜ 0.05).Adverse effect rates in oxycontin group and MS contin group were 62.7 ％ (64/102) and 98.0 ％ (99/102)respectively,and the difference was statistically significant (x2 =20.151,P ＜ 0.05).Conclusion Oxycontin and MS contin in the treatment of serious cancerous pain have the same controlling effect.But oxycontin worked better with quick analgesic onset,low incidence and few of adverse reaction.