Hemicyanine is a group of acentric cation-type dyes, in which one side of the conjugated chain is composed of a quaternary nitrogen-containing heterocycle, and the other side of the conjugated chain is connected to substituted nitrogen through an aryl ring. Different chemical constitutions of hemicyanine and its various connecting modes in polymer lead to abundant topological hemicyanine-based polymers, including linear, star-shaped, brush-shaped, dendritic and hyperbranched macromolecules. These polymers have been used for applications in various roles, such as photographic sensitizers, nonlinear optical materials and biomolecular labeling probes. We will give an overview of the synthesis, structure, properties and applications of series hemicyanine-based polymers.