Objective: To investigate changes of polymorphonuclears(PMNs) adhesion and the possible mechanism after burn injury. Methods: Fourteen rabbits were subjected to a burn of nearly 30%TBSA with full-thickness burned area about 30%. PMNs were obtained from blood through Percoll gradient centrifugation. The PMN adhesion molecule CD11a/CD18 was measured by CAMs ELISA. Levels of TNF and PLA2 in plasma were measured by radioimmunoassay. Results: The PMN adhesion molecule CD11a/CD18 in rabbits increased markedly after burn, peaked at 8 h, restored to the level of control after 48 h. The PMN adhesion rate of rabbits also increased markedly after burn , peaked at 8 h, restored to the level of control after 48 h. It was found that there was significant linear relationship between the PMN adhesion molecule CD11a/CD18 and PMN adhesion rate (r = 0.90). The level of TNF in plasma was higher in burned groups than that in 0 group, peaked at once. The level of PLA2 in plasma was higher after burn than in 0 group, peaked at 2 h. Conclusion: The PMN adhesion molecule CD11a/CD18 and adhesion rate are increased after burn injury. The results suggest that CD11a/CD18 plays an important role in PMN adhesion after burn injury. The levels of TNF and PLA2 in plasma rise rapidly after burn injury, and the rise occurs before or at the same time as the changes in PMN adhesion molecule and PMN adhesion rate. They might contribute to the changes in PMN adhesion molecule and PMN adhesion rate after burn injury.