Does early PCD of sterile APFCs benefits patients or increases the secondary infection rate? In view of these problems, we plan to design a randomized controlled trial to compare the outcomes in terms of mortality, secondary infection of peripancreatic collections, organ failure, length of hospital/ICU stay and inflammatory biomarkers between the early-stage PCD of sterile AFPCs and conservative therapy. The aim of this prospective study is to investigate whether early PCD of sterile AFPCs can be used to SAP patients with AFPCs at early stage.