The zirconium phosphate (ZrP)/Nafion 1135 composite membranes were prepared by impregnating method and characterized by SEM, XRD, ac impedance and electron probe microanalysis (EPMA) techniques. The results show that ZrP(alpha-Zr(HPO4)(2)center dot H2O) deposited both on Nafion 1135 membrane surface and in its inner structure, and the amount of deposited ZrP increases with the immersion time. A test of membrane resistance shows that the membrane resistance increases with the immersion time greatly in CVO2+ : CH+=0.009:0.1 mol L-1 H2SO4 + VOSO4 solution than in 0.05 mol L-1 H2SO4 solution. Subsequently, the proton diffusion coefficient (D) over bar (H+) and VO2+ diffusion coefficient (D) over bar (VO2+) in membrane are evaluated. It is found that both (D) over bar (H+) and (D) over bar (VO2+) decrease with the immersion time based on the retarding effect of the deposited ZrP. The proton diffusion coefficient in Nafion 1135 was determined to be 3.412 x 10(-12) m(2) s(-1), and a slightly lower value of 2.827 x 10(-12) m(2) s(-1) was found in Nafion 1135/ZrP5 membrane. However, the VO2+ diffusion coefficient (D) over bar (VO2+) of the Nafion 1135 membrane, 4.012 X 10(-13) m(2) s(-1), is much higher than that of 1135/ZrP5 composite membrane, 0.3226 x 10(-13) m(2) s(-1). The results show that the composite membrane has better permselectivity as to H+ and VO2+ than Nafion (R) 1135 membrane. (c) 2007 Elsevier B.V. All rights reserved.