Objective To investigate the clinical effect of compound Dachengqi Decoction combined with external application of mirabilite in the treatment of acute pancreatitis. Methods A total of 107 patients with acute pancreatitis were randomly divided into observation group with 54 patients and control group with 53 patients. The patients in the control group were given comprehensive Western medicine conservative treatment, and those in the observation group were given enema with compound Dachengqi Decoction combined with external application of the traditional Chinese medicine mirabilite in addition to the treatment in the control group. The two groups were compared in terms of the changes in inflammation level, serum amylase (AMY), electrolytes, and pancreatic imaging findings after treatment, as well as time to the disappearance of clinical symptoms and complications. Results After treatment, both groups had significant reductions in white blood cell count, neutrophil count, C- reactive protein (CRP), and AMY (P<0.05) and significant increases in the levels of K+, Na+, Cl-, Ca2+, and HCO3- (P<0.05). Compared with the control group, the observation group had significantly greater reductions in white blood cell count, neutrophil count, CRP, and AMY and significantly greater increases in the serum levels of Ca2+ and HCO3-(P<0.05). The observation group had significantly lower degrees of swelling of the pancreas and peripancreatic effusion than the control group (P<0.05). The observation group had a significantly lower overall incidence rate of complications than the control group (1.85% vs 15.09%,P<0.05). Compared with the control group, the observation group had significantly shorter time to the disappearance of abdominal pain and abdominal distension, time to first bowel sound, time to diet, and length of hospital stay (P<0.05). Conclusion Traditional Chinese medicine treatment combined with comprehensive Western medicine treatment can improve the treatment outcome of acute pancreatitis, reduce the incidence rate of complications, and shorten the course of treatment.