Polyancrylonitrile nanofiber membrane (PAM) was prepared by using the electrospinning method with a solution of polyacrylonitrile (PAN) in DMF. The pore-diameter of PAMs and the number of PAM’s layer were controlled for the microfiltration (MF) application. In addition, in order to improve the water‐flux, AN‐PEGMA copolymers have been synthesized via free radical polymerization with poly (ethylene glycol) methyl ether methacrylate and azobisisobutylronitrile(AIBN), and then PAN/AN‐PEGMA nanofiber membranes (PAM/APM) were prepared by electrospinning with a mixture of PAN (9 wt%) and AN‐PEGMA (3 wt%) in DMF (88 wt%). The prepared membranes were investigated with FT-IR and E.D.S. It was confirmed through scanning electron microscope (SEM), porometer, and porosity analysis that the porousmembrane with a uniform diameter (400∼600 nm) and a uniform pore characteristics (0.5∼0.4 μm) was prepared. For the MF application, water‐flux measurements were investigated and then the result was shown that the water permeability value of PAM/APMs introduced AN-PEGMA copolymers was relatively higher than that of the PVdF commercial membrane.From these results, PAN nanofiber membranes prepared by electrospinning could be utilized as a MF membrane.