Abstract：Objective：To observe the clinical effect of Tihu Jiegai method for diabetes complicated with constipation and its effect on levels of substance P(SP) and nitric oxide(NO) in serum. Methods：A total of 70 cases of patients with diabetes complicated with constipation were selected， and divided into the treatment group and the control group according to the random number table method，35 cases in each group. During treatment，three patients discontinued the study in the two groups. Finally，a total of 34 cases were enrolled in the treatment group，and 33 cases in the control group. The treatment group was given prescriptions based on Tihu Jiegai method， and the control group was given lactulose combined with mosapride citrate. Both groups were continuously treated for eight weeks. The clinical effect，symptom scores，defecation， mental state， as well as levels of SP and NO in serum were compared between the two groups. Results：The cured and markedly effective rate was 91.18% in the treatment group，higher than that of 72.73% in the control group(P＜0.05). After treatment，scores of dry stool，poor defecation，abdominal distension，tenesmus，and abdominal pain in the two groups were decreased when compared with those before treatment(P＜0.05)，and the scores above in the treatment group were lower than those in the control group(P＜0.05). After treatment，the defecation time in the two groups was shortened when compared with that before treatment，defecation frequency was reduced，and stool characteristics were improved(P＜0.05). After treatment，the defecation time in the treatment group was earlier than that in the control group，defecation frequency was lower，and the improvement of stool characteristics was better(P＜0.05). After treatment，scores of Self-Rating Anxiety Scale(SAS) and Self- Rating Depression Scale(SDS) in the two groups were decreased when compared with those before treatment(P＜0.05)，and the two scores in the treatment group were lower than those in the control group(P＜0.05). After treatment，SP levels in serum in the two groups were increased when compared with those before treatment，and NO levels in serum were decreased(P＜0.05). After treatment， SP level in serum in the treatment group was higher than that in the control group， and NO level in serum was lower(P＜0.05). Conclusion： In the treatment of diabetes complicated with constipation，Tihu Jiegai method can improve clinical symptoms，intestinal motility，and mental state，as well as promote defecation.