Kinetics of SiCl4 into SiO transformation process in oxygen plasma ofstationary reduced-pressure microwave-induced discharge is studied theoretically and experimentally. Calculations and experiments have been carried out for an extended stationary plasma column, limited by substrate tube silica walls (SPCVD technology). The model includes 10 components and 18 major chemical reactions, and gas mixture flow towards plasma column is taken into proper account. The components distribution along the plasma column was registered by emission spectroscopy. The reaction rate constants of SiCln (n<=4) dissociation under the condition of discharge are estimated by comparison of the calculated concentration profiles of the major plasma components with the experimental data on the longitudinal profiles of their emissions.