Tumor cells often display aberrant levels and patterns of cell surface glycosylation, which provides a potential opportunity to develop carbohydrate-based anticancer vaccines for cancer immunotherapy. However, one of the most addressed challenges in this field is the low efficiency of the carbohydrate vaccination due to poor immunogenicity of carbohydrate antigens. In this article, a number of structure-modified GM3 antigen analogues were designed and chemically synthesized. The modified GM3 antigens were conjugated to protein carriers for vaccination. The vaccination results on mice show that the modification on the GM3 antigen could improve the efficiency of the vaccination, and in particular, two glycoconjugates (3-KLH and 8-KLH) elicited higher titers of anti-GM3 antibodies than the unmodified GM3-protein conjugate (2-KLH) did.