A new type of polyether-imide (PEI)-based nanofiltration membranes was prepared by introducing octaglycidyloxypropyl- silsesquioxane (Glycidyl POSS) into PEI matrix for heavy metals ions removal from water. The separation performance of fabricated membranes in Na2SO4, Pb(NO3)2, Ni(NO3)2 and Cu(NO3)2 removal from water as well as their flux and antifouling property was evaluated. Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) analytical method, atomic force microscope (AFM), porosity, contact angle, and water content were also used in membrane characterization. The results indicated higher hydrophilicity, pure water flux (PWF) and salt rejection for PEI-POSS membranes compared to neat PEI ones. The morphological images showed good tuning porosity, finger- and spongy-like structure. The highest porosity observed for [PEI-1 wt% glycidyl POSS] with the best antifouling property. The surface roughness also decreased by incorporating of POSS into PEI matrix. The pure water flux increased from 14.3 (L/m2h) for neat PEI membrane to 36 (L/m2h) for [PEI-0.1 wt% glycidyl POSS]. Moreover, Na2SO4, Pb(NO3)2, Cu(NO3)2 and Ni(NO3)2 rejection measured 78%, 94%, 99%, 42% for [PEI-1 wt% glycidyl POSS] membrane, whereas they were 69%, 44%, 40% and 16% for the virgin PEI membrane, respectively. Results showed a good potential for [PEI-POSS] membrane in Cu and Pb ions removal beside its high PWF and antifouling ability.