The TEM, XPS, and XRD methods were used to study the influence of conditions of catalyst preparation on the activity and stability of platinum on alumina catalysts in methane oxidation reaction. The catalyst samples were prepared by wet impregnating the γ-Al2O3 support with the solutions of precursors prepared on the commercial platinum nitrate. In the course of the study the composition of the precursor solution and pretreatment of the support were varied. It was shown that the highest catalytic activity and stability to sintering of the active component nanoparticles in methane oxidation is reached in the case of strong interaction of the active component with the support surface providing for the stabilization of the ionic forms of platinum. The use of modifying additives (tetramethylammonium hydroxide, glacial acetic acid) facilitates reduction of the active component both in thermal treatment and in catalytic reaction, which causes a decrease in catalytic activity and stability of the system under used conditions.