Objective. To investigate the effects of Qiang Gu Kang Wei compound on hemorheology in tail-suspended rats. Method. Rats were tail-suspended (-30 degrees) for 21 d to simulate weightlessness. The effect of the compound on erythrocyte sedimentation rate (ESR), hematocrit value (HCT), plasma fibrinogen content (PFC), blood viscosity, red blood cells deformability and erythrocytes aggregation were examined. Result. PFC, whole blood reducing viscosity (eta h), whole blood viscosity (eta b), erythrocyte rigid index (IR) and maximum aggregation index (MAXD) increased significantly (P<0.01 or P<0.05 ) and maximum deformity index (DImax) (P<0.01) decreased significantly in suspended rats as compared with the normal control. Different doses of the compound showed different effects. The small dose group (10 g/kg) inhabited eta h and eta b (P<0.01 or P<0.05) of all shear rates, abnormal IR and MAXD (P<0.01); The middle dose group (20 g/kg) decreased PFC (P<0.01); The big dose group (30 g/kg) inhabited eta h and eta b (P<0.01 or P<0.05) of high shear rates, decreased IR (P<0.01), and improved DImax (P<0.01). Conclusion. This compound could improve hemorheology in tail-suspended rats. But there was no concentration-dependence.