The invention discloses an identification method for fast-growing milkvetch root and wild milkvetch root. The identification method comprises: drying milkvetch root, and crushing; sequentially removing water-soluble components, fat-soluble components and starch from the milkvetch root powder by using a PBS buffer liquid, 80% ethanol, acetone and amylase; carrying out graded mixing on the treated milkvetch root powder sequentially by using a EPG solution, a NaCO3 solution, a 1 M KOH solution and a 4 M KOH solution to extract milkvetch root pectin polysaccharides and hemicellulose polysaccharides; sequentially washing the extracted pectin polysaccharides and the extracted hemicellulose polysaccharides, removing impurities, and carrying out free drying to obtain polysaccharide powder; and carrying out acid hydrolysis, acetylation and GC-MS analysis, and treating the data by using SMICA13 and SPSS software to obtain the molar ratio of the arabinose in the hemicellulose polysaccharide to the arabinose in the pectin polysaccharide, wherein the identified milkvetch root is the fast-growing milkvetch root when the ratio is more than 0.5, and the identified milkvetch root is the wild milkvetch root when the ratio is less than 0.5. According to the present invention, the detection sensitivity of the method is high, the polysaccharide component ratio identification is simple and is easy to operate, and the basis is provided for the identification of the milkvetch root herb source.