Abstract: Objective: To evaluate the safety and efficacy of tilidine hydrochloride in the treatment of moderate Objective: To severe cancer pain.Methods: Thirty-three cancer patients were randomly divided inObjective: To experimental group(18 cases) and control group(15 cases). Theexperimental group and control group were treated with 100 mg tilidine hydrochloride and 20 mg morphine sulfate 4 times daily for 5 days， espectively. The intensity of pain and adverse reactions were observed by numeral rating scale(NRS). The blood and urine routine， electrocardiogram and hepatic and nephritic function were detected at baseline and the sixth day. The signs and sympObjective: Toms and efficacy and safety of laboraObjective: Tory examination of two groups were evaluated at the end of treatment.Results: The NRS score of experimental group was 7. 28 1. 32 before tratment. On the No. 2nd，3rd，4 th and 5th days of treatment， the scores were 4. 94 1. 02，4. 00 0. 99，3. 67 0. 75 and 3. 22 0. 56， respectively. Compared with before treatment， the mean pain scores of two group were obviously improved after treatment，but the differences were not statistical significance(P ＞ 0. 05). The effective and adverse reaction rates of the experimental group and control group were 77. 8% 73. 3% and 33. 3% 40%， respectively， the differences of two group had no statistical significance (P ＞ 0. 05 ). Conclusions: The efficacy for controling cancer pain and adverse reactions of tilidine hydrochloride and morphine sulfate are similar，which can act as first-line treatment for moderate Objective: To severe cancer pain.