Abstract: Polycarboxylic acid is an important type of organic polymer materials. As an anionic polyelectrolyte, polycarboxylic acid has a significant dispersing effect on the particles in the medium, which is widely used as superplasticizer in cement-based materials, paint dispersant, inhibitor in water treatment, etc. In terms of the application of polycarboxylic acid in the field of dispersants, the researches on molecular design by domestic and foreign researchers in recent years were summarized. According to different structural shapes, the molecular structure of polycarboxylic acids was divided into three categories including linear structure, comb structure and branched structure (star-shape and hyperbranched shape). In linear polycarboxylic acid, the block structure has more advantages in performance. As for monomer selection, "green" monomer is the development direction. The comb polycarboxylic acid has unique side chain structure. Among the three synthesis routes, the macromonomer method is the most convenient, the coupling method can be used for special modification, and the initiation method can be used for precise design of polycarboxylic acid molecules. Branched polycarboxylic acids have higher functional group density and stronger steric hindrance effect, and have a broader prospect in molecular design and application. This paper provides an important guidance for future molecular design innovation.