Objective:To explore the effective drug and the best way of administration of the drug in the relief of moderate or severe cancer pain,so as to attain the best effect.Methods:30 patients with moderate or later period cancer orally take 30 mg Morphine tablet every 12 hours. The initial dose was 60 mg,and then it was adjusted according to the effect till the most appropriate dose was reached.Results:After taking Morphine tablet,the rate of complete relief and moderate relief of moderate or severe cancer pain were 70%(21/30),26.7%(8/30),respectively. The total effective rate was 96.7%.Conclusion:Effect of Morphine tablet for cancer pain treatment was sure and reliable,the administration of 30 mg Morphine tablet every 12 hours was safe and effective.