Abstract. The purpose of this work is to determine the optimal configuration of a flowing part of the plenum chamber of the centrifugal compressor of natural gas based on numerical experiment. In the research process was the analysis of the gas-dynamic perfection of a flowing part of the compressor plenum chamber, carried out the calculations to determine the parameters and effectiveness of the plenum chamber by methods of computational fluid dynamics. The result of the work revealed the shortcomings of the original design and determine the expected performance and efficiency optimized plenum chamber.