Objective,2,To observe the clinical efficacy of press needle combined with opioid analgesics in treating moderate-to-severe cancer pain and its effect on serum levels of β-endorphin and substance P.,Methods,2,Seventy-six patients with moderate-to-severe cancer pain were randomized into a treatment group （,n,=38） and a control group （,n,=38）. Patients in the control group received conventional treatment （including active treatment of primary diseases， nutritional support， and opioid analgesics） while those in the treatment group were treated with press needle in addition to the conventional treatment. The treatment in both groups lasted 14 consecutive days. The incidence of adverse reactions was observed， and the pain numerical rating scale （NRS）， Brief Pain Inventory （BPI）， Karnofsky Performance Status （KPS）， and serum levels of β-endorphin and substance P were assessed and compared before and after treatment.,Results,2,①There were 4 drop-outs in the treatment group and 3 drop-outs in the control group during the trial. Finally， 69 patients completed the trial with 34 patients in the treatment group and 35 patients in the control group. ②After treatment， the pain NRS score decreased and KPS score increased in the treatment group （,P,<,0.05）， while the differences before and after treatment in pain NRS and KPS scores in the control group were not statistically significant （,P,>,0.05）； After treatment， the pain NRS score in the treatment group was lower than that in the control group and the KPS score in the treatment group was higher than that in the control group （,P,<,0.05）. ③In the treatment group， the scores of worst pain in last 24 hours， pain on average over the last 24 hours， pain right now， impact on general activity， mood， normal work， sleep， and total score of impact of pain after treatment were lower than those before treatment （,P,<,0.05）， and the scores of impact on walking ability increased after treatment （,P,<,0.05）， but the differences before and after treatment in the scores of the above items in the control group were not statistically significant （,P,>,0.05）； After treatment， the differences between the two groups in the scores of the above items were not statistically significant （,P,>,0.05）. ④After treatment， the serum level of β-endorphin increased and that of substance P decreased in both groups （,P,<,0.05）； After treatment， the serum level of substance P in the treatment group was lower than that in the control group （,P,<,0.05）. ⑤The incidence of constipation， nausea and vomiting and the total incidence of adverse reactions in the treatment group were lower than those in the control group （,P,<,0.05）.,Conclusions,2,Additional use of press needle has a better clinical effect on patients with cancer pain as it can relieve pain， improve patient’s quality of life， and reduce adverse reactions due to opioid analgesics. The mechanism may be related to the regulation of serum β-endorphin and substance P expression levels.