Abstract Nano-sized SnO2 particles were prepared with an argon plasma jet using SnCl4 and O2 as raw materials. SnCl4, which was easily vaporized at room temperature, and O2 were injected into the reactor through the reaction tube in the vapor phase by an Ar-carrier gas. The product of the reaction with the argon plasma jet was synthesized by rapid quenching. Most of the prepared powders were collected on an inside wall of the reactor. Because this process does not need any other after-treatment, SnO2 powder could conveniently be synthesized. As a process parameter, the flow rate of oxygen gas was kept below the constant flow rate of the carrier gas and additional nitrogen gases. The characteristics of the powders were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). TEM and SEM analysis found the particle sizes of SnO2 to be from 3 nm to 20 nm, and images of the particles were also produced. The cross stripes on SnO2 powder also have been studied. The effects of O2 parameters were investigated to optimize synthesis of tin oxide with XRD analysis. An increase in O2 concentration does not ensure good results; therefore it was possible to find optimum conditions for synthesis of SnO2 particles.