Abstract: OBJECTIVE To observe the expressions of serum cell adhesion molecule-1 (ICAM-1), peripheral blood microrna-22-3p (miR-22-3p) and microrna-21-3p (miR-21-3p) in the severe acute pancreatitis patients complicated with abdominal infection. METHODS A total of 90 severe acute pancreatitis patients who were complicated with abdominal infection and treated in the Second Affiliated Hospital of Fujian Medical University from Jan 2021 to Aug 2022 were assigned as the infection group, meanwhile, 102 patients with simple severe acute pancreatitis were chosen as the no infection group. The expression levels of peripheral blood ICAM-1, miR-22-3p and miR-21-3p were statistically analyzed, the values of the indexes in prediction of abdominal infection in the severe acute pancreatitis patients were analyzed by means of receiver operating characteristic (ROC) curve, and the expression levels of the indexes were observed and compared among the patients with different treatment outcomes. RESULTS The expression levels of peripheral blood ICAM-1, miR-22-3p and miR-21-3p of the infection group were higher than those of the no infection group (P＜0.05). The area under curve (AUC) of the joint detection of the three indexes was 0.923 in prediction of abdominal infection in the patients with severe acute pancreatitis, with the sensitivity 92.22%, the specificity 81.37%; the expression levels of the three indexes of the death group were higher than those of the survival group(P＜0.05). CONCLUSION The peripheral blood ICAM-1, miR-22-3p and miR-21-3p have high values in prediction of the complicated abdominal infection in the patients with severe acute pancreatitis and may affect the prognosis of the patients.