The present invention relates to folic acid-polysaccharide complexs and method of preparation thereof, more particularly relates to folic acid-Dextran complexs, method of preparation thereof, pharmaceutical compositions having said complex as active component and uses of said composition in therapy of tumors. The folic acid-polysaccharide complexs of the present invention have general formula of: (X)_n—Y, wherein X is identical or different, and is selected from folic acid, derivatives of folic acid and other substances that can enter into cell via the pathway of folic acid receptor; Y is polysaccharide; n1.