The characteristics of the radio frequency plasma jets at atmospheric pressure in Ar/SiCl4/H2 gas mixture were studied in this paper by using optical emission spectroscopy. Firstly, the electron excitation temperature of plasmas was calculated from the Si atom spectral emission using Boltzmann plots, and then, based on the temperature, the number density of the Si atoms in the plasmas and the dissociation ratio of the SiCl4 were estimated. Finally, the dependence of the excitation temperature, the number density of the Si atoms and the dissociation ratio of the SiCl4 on the discharge power and the gas flow rate were presented.