The dual-layer nanofiber membranes were fabricated by electrospinning. The heat-press post-treatment can improve water flux and keep stable salt rejection. The heat-pressed PH/N6 nanofiber membrane gained the highest water flux. The mass transfer resistance of a hydrophilic layer is lower than a hydrophobic layer. The heat-pressed dual-layer nanofiber membranes were suitable for long-term AGMD.