Abstract： Objective To analyze the optimal timing of endoscopic stone extraction combined with extracorporeal shock wave lithotripsy (ESWL) in the treatment of chronic pancreatitis (CP) with pancreatic stones. Methods Data regarding 170 pancreatic stone patients receiving ESWL and endoscopic stone extraction at Shanghai Changhai Hospital from February 2014 to February 2015 were retrospectively analyzed. Based on the the prior history of endoscopic treatment,patients were divided into group A and B,and then sub-divided into three groups according to the timing of endoscopic intervention after ESWL including <12 h,12~36 h and >36 h subgroup. The success of pancreatic ductal cannulation, clearance of stone in the main pancreatic duct, and ERCP-related complications were evaluated. Results Among all the enrolled 170 patients,107 previously received ERCP(group A) while the others didn't(group B). The overall success rate of cannulation and clearance rate of stones at different times showed no significant difference. The success rate and clearance rate in group A in <12 h,12~36 h and >36 h subgroup were 91.7%,95.2%,78.0%,and 91.7%,95.2%,80.0%,and no significant difference existed. In group B, the success rate and clearance rate in <12 h, 12~36 h and >36 h subgroup were 66.7%, 71.4%, 96.3%, and 60.0%, 76.2%, 92.6%, and the differences were statistically different. The success rate and clearance rate of >36 h subgroup in group B were obviously higher than that in <12 hours (P=0.025) and 12~36 h subgroup (P=0.04). The timing of endoscopic stone extraction did not influence ERCP-related complications. Conclusions Early endoscopic stone extraction after ESWL can be considered in patients with pancreatic stones who previously underwent ERCP. Delayed endoscopic stone extraction after ESWL is recommended in patients without prior ERCP,which can help promote the therapeutic efficacy.