Objective To investigate the morphologic change and phosphatidylserine (PS) exposure of erythrocytes in sepsis patients.Methods 30 healthy volunteers (control group)and 30 sepsis patients were enrolled in this study and were collected venous sampling.Monitoring included Wright's staining blood smear test,erythrocyte aggregation index and the ratio of PS exposure of erythrocytes.A flow-cytometric assay based on FITC-Annexin V was used to measure the PS exposure of erythrocytes.Results The morphological changes of red blood cells included acanthocyte,lachrymiform,rouleaux,spherocyte in sepsis patients,and the peripheral blood erythrocyte aggregation and aggregation index were significantly higher than that of the healthy control group (P＜0.05).The percentage of PS exposure of erythrocytes in sepsis patients were significantly higher than that of healthy volunteers (P＜0.001).Conclusion The PS exposure of erythrocytes were significantly higher in sepsis patients,and the morphology of red blood cells is obvious abnormal.