The influences of different biogas slurry concentrations and soaking time on the seed germination and physiological characteristics of Astragalus membranaceusvar. mongholicus seedling were studied by the culture dish germinationexperiment.And germination power，germination index，vigor index，root and seedling length，root height，content ofchlorophyll and MDA，antioxidant enzyme activities and root activity in various biogas slurry concentrations(0%，10%，25%，50%，75%)and soaking time(4，5，6h)were recorded and analyzed with PCA analysis，and the best biogas slurry soaking concentration and time were explored to improve the yield and quality of Astragalus membranaceusvar. mongholicus.Theresults showed that，the germination power of seeds was the highest in 25% biogas slurry soaking for 5h，which was significantlyhigher than that in water soaking for 4 and 5h( P<0.05).The germinationindex，vigorindex，rootlength，rootweight，Chlacontent，Chlbcontent，Chla+Chlbcontent，rootactivity，POD and SOD activity of seeds under 25% biogas slurry soaked for5 h were significantly higher than the other 14 soakingtreatments( P<0.05).The seedling height of seeds under 25% biogasslurry soaked for 4 and 6 h was thehighest( P<0.05).MDA content and CAT activity of seeds under 25% biogas slurry soakedfor 5 h were thelowest( P<0.05).It can be concluded that appropriate biogas slurry soaking can improve the germination and growth of Astragalus membranaceusvar.mongholicus.As awhole，soaking for 5 h in 25% biogas slurry had the best effect on seed germination and growth of Astragalus membranaceusvar.mongholicusseedling.