Abstract: The invention relates to a method for plasma chemical surface modifying of materials and items, and specifically for plasma aided impregnation with solutions containing fire retardants to make porous materials. The subject matter of the invention is solved by the method of plasma chemical surface modification of porous materials and workpieces to provide fire spread and ignition resistance consisting in autoclave high pressure impregnation and further drying at room temperature, a characteristic of which is that before the impregnation the surface of the material or the workpiece is submitted to a treatment for a period of 3 to 300 seconds with cold non-equilibrium plasma of glow electrical discharge at atmospheric pressure that burns under voltage of 1 to 3 kV and at a frequency of 50 Hz to 100 kHz.