Fabrication of polymer electrolytes with high conductive and mechanical properties simultaneously is a great challenge. Here, a bifunctional polymer, poly(3-hydroxy, 4-sulfonated styrene), was successfully synthesized. The “intra-monomer” hydrogen bond formed between these two functional groups can greatly weaken the electrostatic interactions. For this reason, the stacking of the benzene rings are greatly changed compared to those in the poly(4-sulfonated styrene) and poly(3-methoxy, 4-sulfonated styrene). By doping with ionic liquids, the formation of ion clusters is depressed and the separated ionic liquid phase is formed in the bifunctional polymer electrolyte. The conductivity of 0.8 mS/cm and the storage modulus of ~ 100 MPa are achieved at 25 ℃. Moreover, the activation energy is smaller than that of pure ionic liquid, indicating the antifreezing behavior of the bifunctional polymer electrolyte.