To avoid particle agglomeration and to improve membrane antifouling property, commercial TiO2 particles were modified with polyaniline (PANI) by in situ polymerization. SEM and FTIR analysis confirmed the incorporation of PANI on the surface of the TiO2 particles. The average size of PANI/TiO2 nanoparticles is in the range of 10-67 +/- 3 nm. The preparednanoparticles are used as surface and inner nanofiller additives and dispersed into the polysulfone (PSf) to obtain ultrafiltration nanocomposite membranes via phase inversion method. The surface hydrophilicity of nanocomposite membrane increases with increasing nanoparticles (0 to 1.5 wt %) concentrations. The membrane morphology indicates that nanocomposite membranes exhibited larger surface pore size, higher porosity, more finger like pores, and less macrovoids than the control PSf membrane. The experimental results indicate that the 1.0 wt % of PANI/TiO2 content membrane depicted excellent hydrophilicity, water permeability, and better antifouling property with high rejection. Bovine serum albumin and humicacid were used as model foulants. The protein adsorption study showed that PANI/TiO2 content membranes adsorbed more at the isoelectric point of BSA solution and decreased as the solution pH increases. Higher nanoparticles content (1.5 wt %) membrane outcomes are elucidated and affected and resulted in significant particle agglomeration. Finally, obtained experimental results show that the nanocomposite membranes have higher flux and better antifouling property than the control PSI membrane.