Disclosed are a difluoro benzotriazolyl solar cell polymeric material and preparation method and use thereof; the copolymer has a structure as represented by formula (I), wherein both R1 and R2 are alkyls from C1 to C20, and n is an integer from 10 to 100. In the difluoro benzotriazolyl solar cell polymeric material of the present invention, because the 1,2,3-benzotriazole copolymer contains two fluorine atoms, the HOMO energy level will be reduced by 0.11 eV while the fluorine-substituted 1,2,3-benzotriazole has two imido groups with strong electron-withdrawing property; the fluorine-substituted 1,2,3-benzotriazole is a heterocyclic compound with strong electron-withdrawing property, and an alkyl chain can be easily introduced to the N-position of the N—H bond of the benzotriazole; the functional group of the alkyl chain can improve solar energy conversion efficiency, thus solving the low efficiency problem of polymer solar cells.