Structure and magnetic properties of Co1-xCuxFe2O4 were investigated. Cobalt ferrite has been synthesized by double sintering ceramic technique. X-ray Diffraction (XRD) analysis and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 38 − 46 ± 3nm which is a good result for this method of preparation. The magnetic susceptibility was studied at different temperature as a function of magnetic field intensities. The room temperature hysteresis loop was performed for the present samples in the field intensity of 108kOe using VSM. The parameters of X-ray density (dx) and apparent density (da) increases with increasing Cu+2 concentrations in the prepared samples.