〔Abstract〕 Objective To detect exosomes concentration changes in manual platelet with different storage time and further investigate the effects of exosomes on coagulation function. Methods After divided into storage bags with same volume, the platelets were stored for 0, 3, 5 days(D 0, D 3, D 5) in(22±2)℃. Exosomes were isolated from platelet samples by ultracentrifugation. Western blot、transmission electron microscope and nano-flow cytometry were adopted to characterize exosomes. Meanwhile, exosomes particles concentration was detected by nano-flow cytometry. Exosomes with different storage time were added to plasma, then the effects on the plasma prothrombin time(PT) and activated partial thromboplastin time(APTT)were detected by the automatic coagulation analyzer. Expression of coagulation factor VII on exosomes from platelet stored for different time were tested by Western blot. Exosomes samples of D 0, D 5 were incubated with fresh whole blood, respectively. Then the coagulation indexes of each samples were detected by Thromboelastography test(TEG). Results Test showed the presence of TSG 101, CD 9, which were exosome specific markers. And the exosomes showed a double-layer membrane and cup-like structure. Moreover, the particle size distribution of exosomes was mainly between 60～80 nm. The concentration of exosomes stored for D 0, D 3, and D 5 were(13.86±7.93)×1012,(23.69±12.80)×1012,(45.81±25.87)×1012particles/L, respectively. Compared with D 0, the concentration of exosomes stored for D 3 and D 5 increased significantly(P<0.01), with 1.8 times and 4.0 times, respectively. Compared with the control group, PT in the D 0 and D 5 exosomes group could be decreased by[(0.16±0.15) s, P<0.01]、[(0.36±0.18) s, P<0.001], APTT could be decreased by [(1.11±1.21)s, P<0.05]、[(2.10±1.14)s, P<0.001], respectively. Semi-quantitative analysis of coagulation factor VII was performed by Western blot and it showed statistically differences in coagulation factor Ⅶ concentration(P<0.05). TEG test showed that the coagulation time R value of control group, exosomes of D 0 and D 5 were(5.46±0.90) min,(5.00±0.67) min,(4.38±1.00) min, respectively, indicating that exosomes had procoagulant activity(P<0.05). Conclusion With the prolongation of storage time, the particles concentration of exosomes in manual platelets continuously increased and the blood procoagulant function of exosomes is significantly enhanced, platelet-derived exosomes during storage may be involved in the procoagulant process through the coagulation factor Ⅶ.