Abstract: OBJECTIVE To observe the effect of compound Rhizoma Corydalis Decumbentis treating mild cancer pain. METHODS Seventy-six patients with the standard of mild pain were divided into two groups randomly. Thirty-eight cases in treatment group were given 2 tablets compound Rhizoma Corydalis Decumbentis each time, three times a day, lasting 2 weeks. Control group was given diclofenac sodium, 50 mg each time, three times a day. The methods and treating periods of treatment group and control group were same. RESULTS The total effective rate in treatment group was 89.5%, and control group was 88.2%, two groups have no significant difference (P>0.05). The side effect of treatment group was only 7.89%, and with minor symptoms, the control group was 23.68%, especially the gastrointestinal reaction and liver damage and kidney damage were very prominent, the symptoms were obvious, and patient tolerance was poor. By statistical analysis, there was significant difference(P<0.01). CONCLUSION The effect of treating mild cancer pain with compound Rhizoma Corydalis Decumbentis is the same with diclofenac sodium, while the side effect is less than the latter.