Mixed matrix polyether sulfone based-graphite nanoparticle nanofiltration membranes were prepared by phase inversion technique. SEM, SOM, 3D surface analysis, water content, water contact angle, tensile strength, salt rejection, water flux, porosity, antifouling measurements as well as antibacterial activity were used in membrane characterization. SOM images showed graphite nanoparticle distribution in the structure of membranes relatively. The cross section SEM showed that incorporation of graphite nanoparticles into the casting solution had significant effect on the appearance structural properties of the membrane. The water flux of modified membranes was higher than the amount for unmodified membrane obviously. Salt rejection also increased from 82% for unmodified membrane to 91.79% for the membrane containing 0.5 wt% graphite nanoparticles. The water content and porosity increased at 0.05 wt% and 0.5 wt% concentration of graphite nanoparticle, and showed decreasing manner at 0.1 wt% and 1 wt% additives ratios. Utilizing 0.05 wt% G-nanoparticles into the polymeric solution made a membrane with smoother and hydrophilic surface that tended to improved anti-fouling properties. The 0.05 wt% G-nanoparticles/PES membrane showed more suitable behavior than other membranes. Moreover, blended membranes showed antibacterial activity against E-coli.