【Abstract】Objective To investigate the correlation between the expressions of serum αamylase, carbohydrate antigen 242 (CA242) and pancreatitis after biliary stent implantation. Methods From January 2016 to January 2020, 179 patients underwent biliary stent placement due to malignant biliary obstruction were selected and divided into 78 patients with pancreatitis and 101 patients without pancreatitis according to the postoperative complications of pancreatitis. The level of serum αamylase was measured by enzyme rate method, the expression level of CA242 in serum was detected by electrochemiluminescence immunoassay. Logistic regression was used to analyze the influencing factors of pancreatitis after stent placement, ROC was used to analyze the predictive value of serum αamylase and CA242 in patients with pancreatitis after biliary stent implantation. Results The levels of serum αamylase, CA242, IL10 and CRP in pancreatitis group were significantly increased at 4 hours after operation (P＜005), and the difference of preoperative and postoperative levels in patients with pancreatitis was significantly higher than that in patients without pancreatitis (P＜005). The expression levels of total bilirubin, direct bilirubin and indirect bilirubin in the two groups were significantly decreased at 1 week after operation (P＜005), and the difference of total bilirubin and direct bilirubin before and after operation in patients with pancreatitis was significantly lower than that in patients without pancreatitis (P＜005). High levels of αamylase, CA242, IL10 and CRP were the risk factors of pancreatitis after biliary stent implantation in patients with malignant biliary obstruction (P＜005). The area under the curve of pancreatitis after biliary stent implantation predicted by serum αamylase and CA242 was 0.883, which was significantly better than 0824, 0826 of αamylase and CA242 single detections (z=2015, 2127, P＜005). Conclusions The elevated levels of serum αamylase and CA242 in patients with malignant biliary obstruction after biliary stent implantation are related to pancreatitis, and the combined detection of the two is of high value in the diagnosis of postoperative pancreatitis.