The invention discloses a fuel-
cell bipolar plate with a nitrified and enhanced surface and a preparation method thereof and belongs to the technical field of 
fuel cells. The bipolar plate is prepared by the following steps of: preparing a nitrified layer, a 
chromium-
nitride thin film and a carbon-based nano composite conductive thin film on the two side surfaces of a matrix of a stainless-steel plate or a 
titanium-
alloy plate in sequence, cleaning and 
drying the matrix of the stainless-steel plate or the 
titanium-
alloy plate, then putting the matrix in vacuum-arc 
ion-plating equipment, introducing 
nitrogen and 
hydrogen under the vacuum condition, starting bias 
voltage and hot wires, and preparing the nitrified layer; and introducing 
argon-
nitrogen mixed gas, preparing the 
chromium-
nitride thin film, opening a carbon target and preparing the carbon-based nano composite conductive thin film. The fuel-
cell bipolar plate disclosed by the invention has the advantages that an 
ion nitrification technology is introduced into the field of 
surface modification of the fuel-
cell bipolar plate, and the nitrified layer is prepared on the surface, so that the 
passivation of the matrix can be avoided, the condition that a 
coating fails due to 
corrosion can be effectively prevented; and a stepped transition method is adopted for multi-
element composition of the 
chromium-
nitride thin film and the nano composite conductive thin film, so that the peeling of the 
coating in the use process due to overlarge 
internal stress and oversmall bonding force is prevented.