The invention discloses a flow field plate of a proton exchange membrane fuel cell. The flow field plate comprises a metal substrate and a coating arranged on the metal substrate; the thickness of themetal substrate is equal to the thickness of an aluminum flow field plate body; the coating comprises an anti-corrosion coating body, polyacetylene layers and graphene metal composite membranes; thethickness of the aluminum flow field plate body is 100-200 microns; a flow channel is formed in the aluminum flow field plate body; the anti-corrosion coating body is a dense graphene coating body formed on the surface of the aluminum flow field plate body; the polyacetylene layers and the graphene metal composite membranes are alternately and repeatedly arranged on the outer side of the anti-corrosion coating body; and the number of times of repetition is 3-8. The flow field plate has the advantage that the problem of corrosion to the aluminum flow field plate body in a fuel cell environmentcan be solved.