The one-step preparation of precursors for MnOx/Al2O3 catalytic systems for high*temperature incineration is a promising technology for the catalysts. The aim of the research is to establish the effect of manganese ions (II) concentration on catalytic properties of nanofibrous aluminum oxyhydroxide, modified with manganese ion (II) at methane complete oxidation. Methods: photocolorimeter, chromatography, X-ray analysis. Results: The authors have synthesized nanofibrous aluminum oxyhydroxide (AlOOH), modified with different amounts of manganese ions (II), which is the precursor for methane deep oxidation catalysts. It was shown that the catalytic activity of the manganese-based system obtained depends on manganese amount and thermal activation conditions. It was ascertained that the most promising catalyst for methane high*temperature combustion is a system with manganese content in the precursor 5,7 wt. %. This catalyst does not change its phase composition during the operation; 50 % methane conversion is achieved at 530 °C, as compared with the system with manganese content in the precursor of 10,5 wt. %, where 50 % conversion is achieved at 680 °C. Use of the catalyst with manganese content of 5,7 wt. % allows you to run and to turn heat convectors autothermally when heating catalyst bed to 500…530 °C.