Objective To study the effect of external application of Wuwei Shuangbai Powder on relieving primary liver cancer pain and to observe its effect on hemorheology indexes.Methods A double-blind,randomized and controlled trial was carried out in 60 primary hepatocellular carcinoma patients with cancer pain.The patients were divided into control group and treatment group,30 cases in each group.The treatment group was given external application of Wuwei Shuangbai Powder and oral use of placebo capsules,and the control group was given external application of placebo powder and oral use of celecoxib capsules.The treatment for the two groups lasted for 7 days.Before and after treatment,pain was scored by Numeric Rating Scale (NRS),and the peripheral blood hemorheology indexes of both groups were observed.Results (1) After treatment,the NRS pain scores of both groups were decreased compared with those before treatment (P ＜ 0.05 or P ＜ 0.01),and the scores of the treatment group were significantly lower than those of the control group (P ＜ 0.05),indicating that the treatment group had better effect on relieving cancer pain.(2) After treatment,the indexes of hemorheology of treatment group were significantly higher than those of the control group,and the differences of the indexes except the hematocrit were significant between the two groups(P ＜ 0.05 or P ＜ 0.01).Conclusion Wuwei Shuangbai Powder is effective for the treatment of primary liver cancer pain.The mechanism may be related to the improvement of hemorheology of liver cancer patients.