An experimental study is provided for features of exothermic reaction front propagation during combustion of a mixture ot boron with oxygen-containing agents in relation to boron powder properties. It is shown that the combustion rate for boron-containing heterogeneous condensed systems based on oxidizing agents of sodium nitrate and ammonium perchlorate is proportional to the boron specific surface in the composition and it is a linear function of the boron particle surface accessible for direct contact with the oxidizing agent.