The present study investigated the cytoprotective effect of a polysaccharide from Radix Astragali(APS) and the possible mechanism involved with Akt signal pathway.The effect of APS on human microvascular endothelial cells(HMEC-1) cell viability was tested by MTT.The cell protective effect of APS was measured by Oxygen Glucose Deprivation(OGD) induced ischemia and cell death was measured by LDH assay.Meanwhile,the effect of APS on phosphorylation of Akt by Western blotting was investigated and the Akt inhibitor Wortmannin was used as a blocking agent to test the role of Akt in which signaling pathways play in the cytoprotective effect of APS.The results showed that APS has no significant effect on HMEC-1 cells viability and can remarkably prevent cells from death induced by OGD in a concentration-dependent way.Meanwhile,the results showed that APS could induce phosphorylation of Akt.This cytoprotective effect of APS could be abolished by the Akt inhibitor wortmannin.It can be concluded that APS probably protects cells from death induced by OGD through inducing phosphorylation of Akt.