Abstarct: Nowadays, the use of membrane separation technology is a new and applied technology in the separation of dyes. The aim of this study was to investigate the fabrication of two new nanocomposite polymeric membranes baxsed on polyvinylidene fluoride (PVDF) and to study the mechanism of removal of reactive red dye 120 by the synthesized membranes. For this purpose, clinoptilolite nanoparticles modified with hexadecyltrimethylammonium bromide surfactants (HDTMA-modified clinoptilolite) and NiFe2O4-SiO2 nanoparticles (synthesis by sol-gel method) were prepared. Then, by adding these nanoparticles to the polymer matrix, an attempt was made to improve the hydrophilic and antifouling properties of polyvinylidene fluoride (PVDF) membranes and to improve its performance in removal of the reactive red dye 120 from aqueous solution. For this purpose, pure and nanocomposite membranes of polyvinylidene fluoride were fabricated by wet phase inversion method. The prepared nanoparticles were evaluated using X-ray diffraction (XRD) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Various instruments and methods were used to investigate different aspects of the membranes including field emission scanning electron microscope (FESEM) for membrane morphology, atomic force microscope (AFM) for the surface roughness, fourier transform infrared (FTIR) spectroscopy for membrane functional groups, contact angle (CA) for the hydrophilicity of the membrane surface and pure water permeability measurement test for the pore size and porosity of the membrane and compare them with each other using the Guerout-Elford-Ferry equation and FESEM images of the membrane surface. Also, the separation properties of the produced membranes were determined by permeability test. The results of pure water permeability test and determination of membrane pore size showed that the produced membranes are all classifiable in the nanofiltration range. By adding nanoparticles, the average radius of membrane pores was reduced from 5.72 nm in pure membrane to 4.41 nm in membrane containing 2.5 wt% clinoptilolite nanoparticles modified with hexadecyltrimethylammonium bromide surfactant and 4.39 nm in membrane containing 0.3 wt% NiFe2O4-SiO2 nanoparticles. Results of the contact angle in the pure membrane (CA = 77.5o) and in nanocomposite membranes containing 2.5 wt% of modified clinoptilolite nanoparticles (CA = 63.7o) and 0.3 wt% of NiFe2O4-SiO2 nanoparticles (CA = 51.7 o) showed that by adding the nanoparticles, the hydrophilicity of the membrane surface increases. Findings from the study of fouling parameters and flux recovery ratio showed high anti- fouling properties of membranes containing 0.3 wt% NiFe2O4-SiO2 nanoparticles (FRR = 97%). Also, the nanocomposite membranes containing 2.5 wt% of clinoptilolite nanoparticles modified with hexadecyltrimethylammonium bromide and 0.3 wt% of NiFe2O4-SiO2 nanoparticles in comparison with the pure membranes membranes, with separation efficiency of more than 99.5%, had the best performance in the separation of reactive red 120 dyes from aqueous solution.