Erythrocyte aggregation and related parameters were observed in this study.Erythrocyte aggregation index, hematocrit and fibrin fibrinogen degradation products in-creased significantly at 5 minutes after oleic acid injection. Erythrocyte electrophoretic timein native plasma delayed obviously at 5 minutes after oleic acid injection, whereas that inPBS altered very little. The concentration of plasma calcium and erythrocyte intracellularmagnesium decreased at 5 minutes, while plasma magnesium increased. The stepwise reg-ression analysis suggested that during lung injury the parameters that have greatest effect onerythrocyte aggregation were the change of hematocrit, erythrocyte intracellular magnesiumand negative charge of erythrocyte surface.