Objective: To select the protein extraction protocols for establishing biological fingerprint of Astragali Radix by using PAGE technology. Method: The water soluble protein of Astragali Radix was extracted by 8 different methods (concentrated gel buffer diluted by 4 times

distilled water

Tris-HCl method

the citrate method

PVP buffer

the modified saturated phenol method

TCA-acetone method and protein extract solution) and the PAGE experiment was conducted. The optimal protein extraction protocols for establishing biological fingerprint of Astragali Radix were selected according to the number and the definition of the protein bands. Result: The content of protein extracted by protein extract solution

concentrated gel buffer diluted by 4 times and Tris-HCl buffer was higher

but it showed a higher content of impurities

a dn some characteristic peaks cannot effectively isolated;the content of bands of protein extracted by TCA-acetone method

the modified saturated phenol method

PVP buffer and citrate buffer were lower

with a smaller number of bands and lower definition;bands of protein extracted by distilled water were most numerous and stabler

with a higher separation among peaks in electrophoresis fingerprint. Conclusion: The protein solution extracted with distilled water is more suitable for establishing the protein fingerprint of Astragali Radix.