Kinetic analysis of the thermal partial oxidation in the H2S-H2O-O-2(air) mixture in a flow reactor with given length is conducted numerically on the basis of developed reaction mechanism. This mechanism incorporates the reaction paths typical both for the H2S pyrolysis and for the H2S oxidation and describes with reasonable accuracy a large set of experimental data. The computations have demonstrated that addition of H2O to the fuel rich H2S-O-2(air) mixture allows one to increase the relative yield of H-2 in the conversion products. At identical fractions of H2S and H2O in the H2S H2O blend the increase in the H-2 relative yield can mount to a factor of 1.5. Though the addition of H2O to H2S leads to the delay of the conversion of H2S, nevertheless, at initial temperature (T-0 = 1000 K) it is possible to occur the conversion process in a shot flow reactor of 1 m length at atmospheric pressure. It has been shown that the formation of additional amount of H-2 in the conversion products upon the H2O admixture to H2S is caused by the increase of the role of reaction H2O + H = OH + H-2. The growth in the initial temperature of the H2S H2O-O-2(air) mixture increases the absolute concentration of H-2 in the conversion products and its relative yield. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.