In this paper, Ga-doped ZnO nanoparticles (GZO) are synthesized by solvothermal method with different precursors and Ga doping concentrations: 0%, 1%, 3%, 5%, 7% and 9% at the same temperature of 250 °C in the oleylamine solvent. The structural, morphological and optical characteristics were studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-Vis absorption spectra. Particle size and morphology are strongly influenced by changes in precursor Zn and Ga. The concentration of doping Ga also affects the morphology, structure and optical properties of GZO particles. When Ga doping concentration increased from 0 to 9%, the nanoparticle size changed in the range of 18-45 nm. GZO nanoparticles have relatively high transmittance and GZO-5% sample reaches the highest value at 85% at 550 nm. This suggests that these nanoparticles are promising to make nanocomposite films applied in transparent conductive electrodes.