The invention discloses a comb-shaped polymer for crude oil pour point depressants, a preparation method of the polymer and an application of the polymer, and belongs to the technical field of preparation of polymers and crude oil pipeline transportation. The preparation method includes the steps: a, adding acrylic high-carbon alcohol ester, acrylic perfluor alcohol ester, dicyclopentadiene, firstinitiating agents and first solvents into a reaction vessel, and performing reaction to obtain an acrylic high-carbon alcohol ester-acrylic perfluor alcohol ester-dicyclopentadiene terpolymer; b, adding second solvents, the acrylic high-carbon alcohol ester-acrylic perfluor alcohol ester-dicyclopentadiene terpolymer acquired in the step a, second initiating agents, free radical concentration conditioning agents and vinyl acetate into the reaction vessel, and performing reaction to obtain the comb-shaped polymer which takes the acrylic high-carbon alcohol ester-acrylic perfluor alcohol ester-dicyclopentadiene terpolymer as a main chain and takes polyvinyl acetate as a side chain. The comb-shaped polymer acquired by the preparation method can effectively reduce a freezing point of crude oil, and exploitation and transportation of the crude oil are facilitated.