We have examined theoretically the stability of porous phosphorene and its application in hydrogen separation from gas mixture by employing first-principles calculations. The selfpassivated pore of phosphorene was designed by removing six phosphorous atoms, reaching to the formation of covalent bonds among marginal atoms spontaneously. The gas permeability and selectivity were obtained for the porous phosphorene membrane. The results indicated that the self-passivated defect in phosphorene is inert to the gas mixture containing N-2, CO, CO2, H2O, and CH4 molecules, and the porous phosphorene performed high selectivity for hydrogen over other gas molecules compared with previous graphene and silicene-based membranes. Our results unveiled the great potential of porous phosphorene as a promising membrane in hydrogen purification. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.