Aluminate cement/graphite conductive composite bipolar plate for proton exchange membrane fuel cells (PEMFC) was prepared by mold pressing at room temperature. The effect of size of graphite particles on the conductivity and the flexural strength of composite bipolar plate were discussed. Resistance to acid corrosion, thermal property and pore size distribution of this composite bipolar plate were also investigated in this paper. The experiment results show that the conductivity and the flexural strength of this composite bipolar plate can be improved by choosing uniform size graphite as conductive fillers. The corrosion current is about 10(-4.5) A cm(-2) from polarization curves of this composite bipolar plate, which shows that this composite bipolar plate is acid corrosion-resistant. At and Ca ions may leach from this composite bipolar plate after 1 M H2SO4 acid corrosion. But At and Ca ions leaching from this composite bipolar plate are only a little percentage of the total Al and Ca ions content in the composite bipolar plate after acid corrosion at 30 degrees C. This composite bipolar plate is also thermally stable from room temperature to 400 degrees C. The large amount of pore in this composite bipolar plate is get capillary pores because of the hydration and solidification of aluminate cement, which make it possess humidifying function during the PEMFC operating. (c) 2007 Elsevier B.V. All rights reserved.