Abstract: [Objective] To investigate the changes of coagulation function and vascular endothelial function in patients with acute pancreatitis at early stage and their clinical significance.[Methods] Patients with acute pancreatitis admitted to our hospital from May 2016 to May 2018 were selected as the research objects and the onset time were less than 24 hours. According to the relevant diagnostic criteria, the included patients were divided into two groups:mild AP (MAP) and severe AP (SAP), with 59 cases in MAP group and 51 patients in SAP group. In addition, 50 healthy people who underwent physical examination in our hospital in the same period were selected as the normal control group (NC). We compared the coagulation function, vascular endothelial function and inflammatory factor changes, and analyzed the relevance between these indicators and the acute physiology and chronic health evaluationⅡ(APACHEⅡ). [Results] In terms of coagulation function, there was no significant difference between the NC group and the MAP group(P>0.05).The PT, APTT, FIB and D-Dimer of SAP group were significantly higher than those of NC group and MAP group, and the difference was statistically significant (P<0.05). In terms of vascular endothelial function, there was no significant difference in RHI between NC group and MAP group (P>0.05).The RHI of SAP group was significantly lower than that of NC group and MAP group, and the difference was statistically significant (P<0.05).There was no statistically significant difference in AI between the three groups (P>0.05). In terms of inflammatory factors, there was no significant difference in IL-6 and TNF-α between NC group and MAP group (P>0.05). IL-6 and TNF-α in SAP group were significantly higher than those in NC group and MAP group, and the difference was statistically significant (P<0.05). The APACHEⅡ scoring of SAP group was higher than MAP, with statistically significant difference (P<0.05). Pearson correlation analysis showed that there was no relevance between PT, APTT, FIB, D-Dimer, RHI, IL-6, TNF-αand APACHEⅡin MAP group (P> 0.05). In SAP group, the PT, APTT, FIB, D- Dimer, IL-6, TNF-αwith APACHEⅡ scores were positively correlated (r=0.49, 0.61, 0.32, 0.37;P<0.05), and the RHI was negatively correlated with APACHEⅡ score (r=-0.27;P<0.05). [Conclusion] The coagulation function and vascular endothelial function were basically normal in MAP patients, while those indicators were abnormal in SAP patients, which were correlated with the severity of the patients. Observation of the changes of coagulation function and vascular endothelial function indexes in AP patients can help to estimate the severity of patients and evaluate the prognosis.