Abstract: In order to separating dyes from dye waste water efficiently, electrospun nanofibrous membrane, which has higher surface adsorption energy and higher porosity than traditional membrane, was used as a novel membrane material to treat dye waste water. This paper has studied the filtration property of PA6/66 electrospun fibrous membrane for 0.1g?L-1 disperse blue 2BLN suspension and weak acid blue N-RL solution with dead-end filtration method under constant pressure o.1MPa. The surface morphology of PA6/66 electrospun fibrous membrane, porous structure, dye particle size and selection property also had been studied by SEM, pore size testing meter, nano-particle size testing meter and ultraviolet-visible spectrophotometer. The results shown that there was a compact cake layer on the surface of the membrane after filtered constantly for 1h, the selection to disperse blue 2BLN was 95.6% and to weak acid blue N-RL was only 35.1%, but the filtration fluxes to these two dyes were similar.