Zinc substituted Nickel ferrite (Ni1-xZnx Fe2O4 with (x=0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) magnetic nanoparticles were synthesized using sol-gel method, Nickel nitrate, ferric nitrate, zinc nitrate were used as raw materials. The samples were characterized by TG-DTA, FTIR, XRD and VSM. The functional group analyzed by FT-IR. The XRD used to analyze phase structure and lattice parameters. The powder calcined at 800̊ C XRD patterns confirmed the formation of Nickel ferrite single phase. The crystallite sizes of Zinc substituted Nickel ferrite particles were calculated using Debye- Scherer’s relation The crystallite size decreases 25 nm to 55 nm ,with increasing the concentration of zinc. TG/DTA measurement showed the weight loss between 0-200˚C, 200-400˚C and 400-600˚C which corresponding the endothermic and exothermic processes. An exothermic peak observed at around 400˚C is due to the thermal decomposition of the ingredients to form Ni Fe2O4. The saturation magnetization value is 0.2 emu/g to 0.7emu/g for the sample sintered at 800˚C.