Abstract: Acute pancreatitis (AP) is a local and systemic inflammation process which is characterized by extensive infiltration of inflammatory cells and outbreak of inflammatory factors. Recent researches have shown that macrophage play a critical role in the process of AP, in particular, peritoneal macro phage as a main innate immune cell in the peritoneal cavity which has been reported not only serve as the first line in host defense, but also help maintaining the immune homeostasis and coordinate the repair and regenerate response by regulating the polarization of their phenotype. Recently, peritoneal macrophages could interact with ascetic fluid of AP patient, and further affect the development and resolution of inflammation. In this review, authors focused on the role and regulatory mechanism of peritoneal macrophage in the progress of AP.