Objective:To study the mechanisms of ameliorating insulin resistance（IR） by astragalus polysaccharides（APS） in rats with IR.Method:Fourty-eight healthy male Sprague-Dawley rats were randomly divided into two groups:the normal control group（NC group

n=12） and the high fat-diet-induced model group of IR（HFM group

n=36）.Rats in the NC group were fed with ordinary diet while those in the HFM group were fed with high fat diet for six weeks.Then the rats in the HFM group were randomly divided into three groups:the high fat-diet-induced control group（HFC group

n=12）

pioglitazone group（Pio group

n=12）

APS group（n=12）

lavaged with saline

pioglitazone（20 mg·kg-1·d-1） and APS（200 mg·kg-1·d-1） respectively for eight weeks.Changes in fasting blood glucose（FBG）

fasting insulin（FINS）

free fat acid（FFA）

resistin and adiponectin of rats were routinely measured

meanwhile glucose infussion rate of tissue was evaluated by hyperinsulinaemic-euglycaemic clamp technique.Result:The levels of plasma FINS

FFA

resistin of rats were significantly higher and the levels of APN

glucose inffusion rate of tissues were significantly lower in the HFC group than those in the NC group（P<0.05）.Compared with those in the HFC group

the above mentioned indexes in APS group were improved significantly（P<0.05）.GIR and the levels of FFA

FINS

resistin

APN were conducted linear correlation analysis and showed significant correlations.Conclusion:The results indicate that APS can regulate part of the insulin signaling in IR serum

and that APS could be a potential insulin sensitizer for the treatment of IR by an increase of adiponectin and reduction of resistin in serum.