Objective: To compare the effects and adverse reactions of dihydrocodeine tartrate and codeine phosphate in treating moderate cancer pain. Methods: Sixty-nine cases of cancer patients with moderate pain were treated with dihydrocodeine tartrate or codeine phosphate respectively by double-blind, controlled randomized methods and the effects and adverse reactions were observed. Results: After administration of dihydrocodeine tartrate or codeine phosphate, in treatment group or control group, the total effective rate was 86.6% and 93.6%, and common adverse symptoms included constipation (31.3%/12.9%), nausea (18.8%/19.7%), gastric trouble (18.8%/19.7%), skin pruritus (12.5%/10%), vomit (9.3% and 6.5%) with the difference being not significant. Conclusion: The effects of dihydrocodeine tartrate in treating moderate cancer pain are similar to codeine phosphate. Both them can be used to treat moderate cancer pain.