<p>The Conversion of SO2 by Hydrogen Oxidation Branching Chain Reaction A.A. Arutyunyan Institute of Chemical Physics after A.B. Nalbandyan NAS of The Republic of Armenia, 5/2 Paruyr Sevak St., Yerevan 0014, Republic of Armenia E-mail: harhasmik@mail.ru The process of SО2 conversion in the hydrogen combustion mode at the following conditions T=500 oC and P<200 Torr (H2:O2:SO2:N2=10:1:1:0.5) has been studied. It is shown that at τк<4.5s the process is characterized by pulsating flames along with the consumption of hydrogen, oxygen and SО2. When leaving the reactor, free sulfur is precipitated on the cold part. The structural features of precipitated sulfur were studied with the help of electron microscopy and X- ray diffraction phase analysis. Key words: sulfur, sulfur dioxide, pulsating flames, free radicals, combustion.</p>