Abstract: Incomplete oxidation nano SnO₂ powder with tetragonal phase was prepared by arc plasma process with Sn as raw material. The relationship between the growth rate and the temperature of SnO₂ powder was studied by different heat treatment process. The original SnO₂ powder was heat treated with different temperatures and holding time. X-ray diffraction(XRD) and scanning electron microscope(SEM) were used to analyze the compositions and morphologies of the samples. The experimental results showed that the grain size of SnO₂ powder prepared by plasma atomization increased in two stages with temperature, and the proper heat treatment process could improve the particle size uniformity.