Objective To investigate the effect of linear echoendoscope guided precise endoscopic sphincterotomy(EST)on positive rates of bile amylase(BA)and bile bacteria as well as occult pancreaticobiliary reflux(OPBR)in patients with calculus of common bile duct after endoscopic retrograde cholangiopancreatography(ERCP).Methods The subjects of this study,146 patients with calculus of common bile duct who underwent EST for ERCP from June 2021 to February 2023,were divided into two groups based on EST type,each with 73 cases.Observation group was administrated with linear echoendoscope guided precise EST,control group was administrated traditional EST.The operation conditions of both groups were observed.Liver function indexes[total bilirubin(TBiL),conjugated bilirubin(CB)and alanine aminotransferase(ALT)],inflammatory and stress indicators[C-reactive protein(CRP),high mobility group box-1 protein(HMGB1),cortisol(Cor),norepinephrine(NE)],and the positive rates of BA and bile bacteria were compared between the two groups before operation and 1,3 days after operation.The postoperative complications and recurrence rate 12 months after operation were recorded.Results There was no significant difference in the success rate of lithotomy and operation time between the two groups(P>0.05).The intraoperative blood loss in the observation group was less than that in the control group,and the hospital stay was shorter than that in the control group,and the differences were statistically significant(P<0.05).1 and 3 days after surgery,TBiL,CB and ALT in two groups were lower than those before surgery,the differences were statistically significant(P<0.05),but there was no statistically significant difference between groups(P>0.05).1 and 3 days after surgery,serum CRP,HMGB1,Cor and NE levels and BA concentration in two groups were higher than those before surgery,and observation group was lower than control group,with statistical significance(P<0.05).The positive rate of biliary bacteria 1 and 3 days after surgery in the control group was higher than that before surgery,the difference was statistically significant(P<0.05);the positive rate of biliary bacteria in the observation group was not significantly different at different time points before and after surgery(P>0.05);the positive rate of biliary bacteria in the observation group was lower than that in the control group 1 and 3 days after surgery(P<0.05).The incidence of OPBR and postoperative recurrence rate at 12 months in the observation group(15.07%and 1.37%)were lower than those in the control group(57.53%and 10.96%),and the differences were statistically significant(P<0.05).Conclusion Linear echoendoscope guided precise EST is more effective in mitigating duodenal papillary sphincter injury,preventing duodenal-biliary reflux,inhibiting BA secretion and bacterial proliferation,and reducing the risk of OPBR than traditional EST.