Abstract: The changes of blood circulation during weightlessness(WL)are simular to the changes of blood-stasis called by Chinesemedicine.So it may be a good method to improve the state of blood cir-culation during WL by using Chinese herb medicine.In this experiment,the effects of four kinds of Chinese herb medicine,which are salviamiltiorrhiza bge+astragalus mongholicus bge(SM-AM),ligusticum walli-chii fanch(LWF),Guan Xin-2(GX-2)and anisodine(AS),on rabbit ear'smicrocirculation and blood rheology in simulated WL were compared.The results showed that the four kinds of Chinese medicines all hadthe effects to improve the blood circulation of rabbit under simulatedWL and the order was SM-AM>LWF>GX-2>AS,and also showed thatthe better dosage of SM-AM was 15g/kg,and the better dosage of LWFwas 10g/kg.