a composite bipolar plate for a polymer electrolyte membrane membrane fuel cell is prepared as follows : a ) melt compounding a polypropylene resin and graphite powder at 100 - 250 ° c . and 30 - 150 rpm to form a melt compounding material , the graphite powder content ranging from 50 wt % to 95 wt % based on the total weight of the graphite powder and the polypropylene resin , and the polypropylene resin being a homopolymer of propylene or a copolymer of propylene and ethylene , wherein 0 . 05 - 20 wt % carbon nanotubes , based on the weight of the polypropylene resin , are added during the melt compounding ; and b ) molding the melt compounding material from step a ) to form a bipolar plate having a desired shaped at 100 - 250 ° c . and 500 - 4000 psi .