Ce3+ ion substituted Sr-hexaferrite magnetic nanoparticles (MNPs), SrCexFe12-xO19 (0.0 ≤ x ≤ 0.5) MNPs, were fabricated by citrate sol-gel combustion approach. All products have been characterized using X-ray diffraction (XRD), Photoluminescence, scanning electron microscopy (SEM), elemental mapping (EDS), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) at 300 and 10 K. The XRD pattern presents effective substitution of Ce3+ on the sites of strontium hexaferrite lattice. With Ce3+ doping, the lattice parameters a is almost unchanged, whereas c is a little increases with increasing the dopant contents. The hysteresis loops M-H showed the ferromagnetic nature of all elaborated. The saturation magnetization (Ms) and the remnant magnetization (Mr) are reduced with increasing Ce amount. All the elaborated products presented typically squarness ratio (Mr/Ms) around 0.5, indicating the existence of non-interacting single domain MNPs with a uniaxial anisotropy. The anisotropy fields (Ha) are found to be very large proving that all products are magnetically hard. With increasing the Ce content, Ha increases which indicate the strengthening of magnetic properties. Consequently, the values of coercive field (Hc) are enhanced, leading these products to be utilized in many uses, such as recording media and permanent magnets. ZFC and FC magnetizations curves indicated shifts of the blocking temperature (TB) to lower temperatures with increasing Ce content. This is accredited to the reducing of particle size with Ce-substitution.