Abstract：Objective：To observe the clinical effect of Runbian tang for constipation caused by cancer．Methods：A total of 78 cases of patients with constipation caused by cancer， diagnosed and treated in the Hangzhou Xiacheng District Traditional Chinese Medicine Hospital and Affiliated Hospital of Hangzhou Normal University from February 2017 to February 2019，were selected and divided into Group A and Group B according to the different treatments，39 cases in each group． Group A was treated with phenolphthalein， and Group B was treated with Runbian tang． The symptom scores， clinical effect，improvement of constipation including the beginning time of defecation，the recovery time of stool morphology and the one- week defecation times as well as the incidence of unfavorable conditions in the first defecation including forced defecation， dry stool， incomplete defecation and sense of obstruction in the two groups were compared. Results： After treatment，the symptom scores in the two groups were decreased when compared with those before treatment，and the score in Group B was lower than that in Group A(P＜0.05). The total effective rate in Group B was higher than that in Group A (P＜0.05). The beginning time of defecation and the recovery time of stool morphology in Group B were shorter than those in Group A， and the one- week defecation times were more(P＜0.05). The incidence of unfavorable conditions in the first defecation in Group B was lower than that in Group A(P＜0.05). Conclusion：Runbian tang has ideal curative effect in treating constipation caused by cancer，which can quickly eliminate the clinical symptoms of patients and improve the constipation.