AIM:To explore the changes of L-selectin expression and F-actin distribution of leukocytes from pancreatic circulation in the experimental acute necrotizing pancreatitis (ANP) rats and impact of Chinese herbs west China pancreatitis yi hao (WPY) on them in vivo. METHODS:Forty-four Wistar rats were randomized into control group,ANP group and ANP WPY treated group. The leukocytes from blood of splenic vein were incubated with PE-anti-CD62L for L-selectin and TRTIC-Phalloidin for F-actin,then the ratio of CD62L positive granulocytes was measured by flow cytometry and leukocytes were taken images with confocal laser scanning microscope. The distribution of F-actin at the border or central part of leukocyte was analyzed by using Mias system. RESULTS:The ratio of CD62L positive granulocytes increased in ANP rats,but those increases at 6 h (31.78%?12.37%) and 12 h (29.83%?13.73%) were significant [vs control group(11.96%?5.32%),P