In this research, Li1.25Mn0.125Ni0.125Co0.5O2 Nano powders, were synthesized using sol-gel method at different temperatures, lithium nitrate, manganese nitrate, nickel nitrate, cobalt nitrate as raw materials. Thermal and thermal gravimetric of TGA/DTA, characterization of structure properties of samples prepared by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) were performed. Also, with X-ray diffraction scheme, at different temperatures, it was concluded that the calcination temperature is suitable for synthesis. The size of Nano crystals was determined using Scherer and Williamson Hall method. The FTIR results showed that the metal bands in the 500 region increased sharply with increasing temperature to 850C, which is consistent with the XRD results.