Abstract： Objective： To observe the analgesic effect of the therapy of modified Shaoyao Gancao tang combined with opioid analgesics on moderate-to-severe cancer pain and its effect on the quality of life of patients. Methods： A total of 68 cases of patients with moderate- to- severe cancer pain were divided into the control group and the experiment group according to the random number table method，with 34 cases in each group. The control group was treated with oxycodone sustained-release tablets，and the experiment group was additionally treated with modified Shaoyao Gancao tang based on the treatment of the control group. The pain relief，degree of pain，frequency of pain flares，dose of morphine hydrochloride tablets for pain flares， quality of life， adverse reactions and the satisfaction rate of pain control in the two groups were compared. Results：The pain relief rate was 85.29% in the experiment group，higher than that of 61.76% in the control group (P＜0.05). After treatment，the numeric rating scale(NRS) scores in the two groups were decreased on the 3rd，7th，10th and 14th days of treatment when compared with those on the first day of treatment (P＜0.05)；the NRS scores on the 3rd，7th，10th and 14th days of treatment in the experiment group were lower than those in the control group at the same time (P＜0.05). Compared with the first week of treatment，the frequency of pain flares and dose of morphine hydrochloride tablets for pain flares in the second week of treatment in the two groups was reduced (P＜0.05)；the above indexes in the experiment group in the second week of treatment were lower than those in the control group (P＜0.05). After treatment，the EORTC QLQC15- PAL scores of patients with advanced cancer in both groups were decreased when compared with those before treatment (P＜0.05)；after treatment，the above score in the experiment group was lower than that in the control group after treatment (P＜0.05). The incidence of adverse reactions during treatment was 17.65% in the experiment group，lower than that of 41.18% in the control group (P＜0.05). The satisfaction rate of pain control was 94.12% in the experiment group， higher than that of 73.53% in the control group (P＜0.05). Conclusion： The therapy of modified Shaoyao Gancao tang combined with opioid analgesics for moderate- and- severe cancer pain can improve the rate of pain relief and effectively reduce the degree of pain， frequency of pain flares of pain， dose of morphine hydrochloride tablets for pain flares and adverse reactions，so as to improve the quality of life of patients and satisfaction rate of pain control.