Objective To study the effect of duodenal papillary morphology on selective biliary cannulation (SBC). Methods Data of 912 patients with biliopancreatic diseases treated with endoscopic retrograde cholangiopancreatography (ERCP) at the Department of Gastroenterology, Affiliated Hospital of Northwest Minzu University from January 2018 to January 2020 were retrospectively analyzed. Duodenal papillary morphology of patients was classified into 4 types by using Haraldsson''s endoscopic classification. The success rate of SBC, the pre⁃incision rate, the difficult intubation rate and the incidence of post⁃ERCP pancreatitis (PEP) of different papillary types were analyzed. Results A total of 912 patients were enrolled in this study, and 86.95% (793/912) duodenal papilla conformed to one type of the classification, of which 77.18% (612/793) were regular type (type Ⅰ), 10.21% (81/793) small nipple type (type Ⅱ), 8.58% (68/793) protruding or drooping type (type Ⅲ), and 4.04% (32/793) wrinkled or ridged type (type Ⅳ). The success rates of SBC in four types of duodenal papilla were 98.86% (605/612), 90.12% (73/81), 88.24% (60/68) and 96.60% (28/32) respectively. The success rate of SBC of type Ⅰ was higher than those of type Ⅱ⁃Ⅳ (all P<0.008) and there was no significant difference between those of type Ⅱ and type Ⅲ (P> 0.008). The pre⁃incision rate in the four types of duodenal papilla were 7.84% (48/612), 32.10% (26/81), 50.00% (34/68) and 25.00% (8/32) respectively. The pre⁃incision rate of type Ⅰ was lower than those of type Ⅱ⁃Ⅳ (all P<0.008), and there was no significant difference between those of type Ⅱ and type Ⅲ (P>0.008). The difficult intubation rate in the four types of duodenal papilla were 12.42% (76/612), 39.51% (32/81), 58.82% (40/68) and 28.12% (9/32) respectively .The difficult intubation rate of type Ⅰ was lower than those of type Ⅱ and type Ⅲ (both P<0.001), and that of type Ⅲ was higher than that of type Ⅳ (P=0.004) . There was no significant difference between those of type Ⅰ and type Ⅳ or type Ⅱ and type Ⅲ (both P>0.008). The incidences of PEP of the four types were 2.61% (16/612), 12.35% (10/81), 5.88% (4/68) and 6.25% (2/32) respectively. The incidences of PEP of type Ⅱ was higher than that of type Ⅰ (P<0.001) , and there was no significant difference between those of type Ⅰ and type Ⅳ or type Ⅱ and type Ⅲ (both P>0.008). Conclusion SBC is affected by duodenal papilla morphology, easiest for type Ⅰ and hard for type Ⅱ and Ⅲ. Attention should be paid to risk of PEP in SBC of type Ⅱ.