For the assessment of the priority of occurrence of heterogeneous catalytic reactions during the pyrolysis of low-molecular-mass hydrocarbon feedstock, laboratory kinetic investigation was performed by means of the pulse technique. Possible mechanisms of the formation of lower olefins were studied. It was shown that the reactions in question substantially differ from one another in values of the rate constants. A deterministic kinetic model for catalytic pyrolysis was proposed on the basis of the surface reaction control principle; the adequacy of the model was evaluated with the use of the probabilistic-statistical model.