N-acyl modified sialic acid (α-(2→6))-D-aminopyranose derivatives, their synthesis methods and uses are disclosed. Sialic acid (α-(2→6))-D-aminopyranose derivatives represented by formula 1 are synthesized by using D-aminogalactose (glucose) and sialic acid as raw materials, which are coupled with carrier proteins or polypeptides to obtain glycoprotein (glycopeptide) conjugates. Acetyl is replaced by derivative acyl in the structures of said compounds, therefore the compounds show good activity in antitumor vaccines.