Cobalt ferrite is a well-known hard magnetic material with high coercivity and moderate magnetization. Its nanoparticles at ambient temperature were effectively synthesized via the reproducible solvothermal process. The crystal structure morphology of the sample was determined by X-ray diffraction (XRD) and Scanning Electron Microscopy(SEM). The X-ray diffraction spectrum shows that the synthesized particle has been spinel structure. The average crystalline size was 32 nm. The SEM observation showed that the CoFe2O4 particle were aggregated in a spherical form and the average particle size was around 35 nm, which is in consistent with the result from XRD according to the Scherrer’s formula. The chemical composition and optical properties of the synthesized cobalt ferrite particles were characterized by FTIR spectrum and UV – Visible absorption.