The definition of POPF released by ISGPS in 2016 still seems to have certain deficiency. For example, in both definitions in 2005 and 2016, the re-operation is used as an important judgment index of "Grade C POPF". But a unified standard or consensus is still lacked for the indication of POPF re-operation, which may finally impact the diagnosis of "Grade C POPF". Therefore, we performed this study, so as to better improve the relevant definition and provide guidance for the diagnosis and treatment.