To study the effect of oxygen enrichment of room air on the change of hemorheology of soldiers after high altitude hypoxia and exhaustion exercise at 3700 altitude, the oxygen concentration was increased to 24 0%～25 0% in the rooms at 3700m altitude, the change of hemorheology in 10 soldiers after they had 12h rest and sleep in the oxygen enrichment room was examined in no oxygen enrichment resting state and in oxygen enrichment state as well as after exhaustion exercise in no oxygen enrichment room and in oxygen enrichment room.Hematocrit (HCT), blood viscosity (?b), reduction viscosity (?r) and viscometric aggregation index (VAI) were higher after exhaustion exercise in no oxygen enrichment room as compared with those in no oxygen enrichment resting state, the difference was very significant or signifant ( P 0 05),?b, Plasma viscosity (?p), ?r were decreased after exhaustion exercise in no oxygen enrichment room ( P