The invention discloses ABA type and ABCBA type block polymers as well as preparation and application thereof and relates to the technical field of high polymer materials. According to the ABA type and ABCBA type polymers, soap-free emulsion polymerization is performed by adopting a bifunctional RAFT reagent and taking acrylic acid as a hydrophilic segment A and acrylate monomer as a hydrophobic segment B or C, and a three-block polymer is synthesized by a two-step method or a five-block polymer is synthesized by a three-step method, wherein the monomer of the segment B or C is a block polymer or copolymer of styrene, trifluoroethyl acrylate, ethyl acrylate, butyl acrylate or hexafluorobutyl acrylate. The ABA type and ABCBA type block polymers are elastomers. The emulsion becomes a transparent film after room-temperature film formation, and a hydrophobic surface is formed after heat treatment, wherein the surface contact angle is up to 120 degrees.