Nickel titanate (NiTiO3) nanoparticles were successfully prepared by wet-chemical method, using nickel acetate and titanium(IV) isopropoxide as Ni, Ti sources and citric acid as complexing reagent. The gel was calcined at different temperatures from 500-700 °C. Results of thermogravimetric analysis (TGA) are given. Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM),transmission electron microscopy (TEM), ultraviolet (UV) spectroscopy, vibrating sample magnetometer (VSM) were used to characterize the crystallization process, particle size, morphology, optical and magnetic properties of the calcined nanoparticles. TEM result reveals that the NiTiO3 was homogeneous and hexagon morphology with the grain size of 30-70 nm. The band gap values of the NiTiO3 nanoparticles were calculated to be 3.43, 3.39 and 3.31 eV. The magnetic property was confirmed that the NiTiO3 nanoparticles of super paramagnetic behavior in nature. Our results suggested that the temperature plays an important role in the particle size effect of nanocrystalline NiTiO3.