Abstract: Antibody drugs often show “heterogeneity”, including the related isomers differing from one another in glycosylation, charge or molecular size. Most of these isomers come from post-translational modifications, such as aggregation, degradation, glycosylation, oxidation, deamidation or disulfide misfolding, of the recombinant protein in the “cell factories”. These modifications not only influence the quality, safety and efficacy of the antibodies, but also serve as an important indication of product quality throughout the whole process of antibody production. This paper reviews the relationship between glycoslation, charge and size heterogeneities of monoclonal antibodies and drug efficacy, safety, pharmacokinetics as well as immunogenicity, contributing to a better understanding of the relationship between antibody structure and function. It will provide some support and guidance for the research and development of antibody drugs, especially biosimilars.