The effect of calcination temperature, varying from 773 to 923 K, on the synthesis of Zn0.5Co0.5PrxFe2-x¬O4 (0 ≤ x ≤ 0.2) by co-precipitation method was discussed in our present work. The X-ray powder diffraction XRD patterns for all the samples confirmed the formation of zinc cobalt nano ferrite with fcc spinel phase and Fd3 space group. The crystallite size calculated from XRD and the particle size measured from the Transmission Electron Microscope TEM increased with the increase of calcination temperature for all samples with different concentrations of Pr3+. The variation of calcination temperature didn’t show any change in the shape of the prepared nanoparticles. The impurity of all samples was investigated by the Fourier Transform Infrared FTIR spectra. UV-vis absorption spectra showed a red-shift with increasing the calcination temperature. The band gap energy Eg, determined from Tauc-plot, decreased with the increase of calcination temperature. This result is in good agreement with the decrease of particle size. ΔHpp and g-value, obtained from the Electron Paramagnetic Resonance EPR spectra, increased with the rise of calcination temperature from 773 to 923 K. The variation of g-value can be an indicator for the rearrangement of cations between tetrahedral and octahedral sites due to the variation of calcination temperature.