The invention relates to the field of crude oil recovery and discloses a polymer having a surface active function, and a preparation method and an application thereof. The polymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is a structural unit of a formula (1), the structural unit B is a structural unit of a formula (2), and the structural unit C is a structural unit of a formula (3). According to the invention, polymerizable monomers having surface activity are introduced into a macromolecular chain, and ether chain structures of the polymerizable monomers determine quite strong hydrolysis resistance and heat stability of a synthesized copolymer, meanwhile, surface tension and interfacial tension of a polymer solution are greatly decreased, and accordingly the polymer has good surface activity, compatibilizing emulsifying and oil washing abilities, so that crude oil recovery rate is increased.