A concept of preparing high-temperature proton exchange membranes with layer-by-layer (LBL) self-assembly technique was proposed and the sulfonated polyetheretherketone (SPEEK) and polyurethane (PU) with 200 LBL deposition cycles denoting (SPEEK/PU)(200) membrane was prepared in this research. Owing to the strong electrostatic interaction between SO3- group in SPEEK and CN+ group in PU, (SPEEK/PU)(200) membrane with LBL self-assembly structure showed a favorable structural stability. The phosphoric acid (PA)-doped (SPEEK/PU)(200) membrane showed a higher proton conductivity relative to PA doped SPEEK/PU membrane by solution casting method (SPEEK/PU)(200)/40%PA membrane possessed a proton conductivity value of 2.90 x 10(-2) S/cm at 150 degrees C under anhydrous conditions. The LBL self-assembly structure provided a possibility to reduce the negative effect from polymer skeleton blocking charge carrier species even immobilizing protons. Moreover, the (SPEEK/PU)(200) membrane presented the particularlynoteworthy mechanical property even with PA doping. The tensile stress values at break were 72.8 and 24.1 MPa, respectively, for (SPEEK/PU)(200) and (SPEEK/PU)(200)/40%PA membrane at room temperature, which were obviously higher than the reported values of 15.9 and 2.81 MPa for SPEEK/PU and SPEEK/PU/60%PA membrane. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3446-3454