Aluminate cement/graphite conductive composite bipolar plates were prepared by mould pressing at room temperature. The effects of the graphite content, the mould pressing pressure and mould pressing time on the electrical conductivity and the flexural strength of composite are discussed. The electrical conductivity and the flexural strength of the composite bipolar plates with 60 wt.% graphite content, prepared with a mould pressing pressure of 5 MPa for 10 min, is > 100 S cm(-1) and 20 MPa, respectively and can be improved by optimizing the mould pressing conditions, especially mould pressing time. The water content of the composite bipolar plate with different graphite contents was also investigated. The water content of the composite bipolar plate is about 6 wt.% with a graphite content of 60 wt.%. This composite bipolar plate contains capillary pores and has hydrophilicity, which is different from other composite bipolar plates. Therefore, it possesses an inner humidifying function and can use the water produced at the cathode for humidifying the proton exchange membrane during the operation of a PEMFC. In addition, the H-2 permeability of the composite bipolar plate is low. (c) 2006 Elsevier B.V. All rights reserved.