Objective To investigate the composition rationality of compound Emodin-Baicalein, and analyze the effects of two components in the treatment of severe acute pancreatitis (SAP). Methods The rat models of SAP were induced by retrograde injection of 5% sodium taurocholate into the common biliopancreatic duct. According to the experimental design of the regularity of recipe composition, male Sprague Dawley rats were randomly divided into the control group, Sham operation group，SAP group, A group (emodin, 3.2mg/kg), 2A group (emodin, 6.4mg/kg), B group (baicalein, 7mg/kg), 2B group (baicalein, 14mg/kg), 1/2AB group (emodin 1.6mg/kg +baicalein 3.5mg/kg)，AB group (emodin 3.2mg/kg +baicalein 7mg/kg) and 2AB group (emodin 6.4mg/kg +baicalein 14mg/kg). All the rats were sacrificed at 12 hours after model preparation. The histopathology score of pancreas and serum amylase activity were determined 12 hours after the surgery to evaluate the drug efficacy. Results Compared with the SAP group, pancreatic histopathological score and serum α -amylase activity decreased significantly in three treatment groups. Compared with groups 2A and 2B, the pancreatic histopathological score and serum α -amylase activity in group AB were significantly decreased. The pancreatic histopathological score in 1/2AB, AB and 2AB groups decreased with the dose increase. Conclusion The effect of AB group was better than that of 2A and 2B groups. There was a synergistic effect between emodin and baicalein in the Compound Emodin-Baicalein. The composition of Compound Emodin-Baicalein was reasonable and has the effect of treating SAP in rats.