The synthesis of nanoparticles by pulsed laser ablation in liquid is a green and environmental-friendly method. Based on this method, a set of induum tin oxide ITO nanoparticles preparation system was built, which used picosecond laser as a light source to irradiate the solid target of ITO in deionized water, and finally synthesized ITO nanoparticles. With the increase of incident pulse energy and laser irradiation time, the laser ablation efficiency increased obviously and ITO production increased. The ITO nanoparticles were characterized by scanning electron microscopy (SEM) and X-ray energy dispersive spectrometer (EDS). The prepared ITO nanoparticles have high purity and did not contain impurities other than Indium (In) and Tin (Sn). In addition, 72% of the ITO nanoparticles had a particle size of 20?50 nm.