The process of separating membranes productivity growth during treatment with gas-discharge plasma ions has been investigated and a method of polymer and metal-ceramic membranes modification by plasma-chemical treatment has been developed. The method allows to obtain membranes with required pore sizes. Plasma treatment of a metal-ceramic membrane with vapors of heterorganic compounds leads to a decrease in the pore size in the surface layer up to 250Ǻ. The use of plasma-modified metal-ceramic and ceramic membranes in the processes of gas purification from solid impurities makes it possible to realize an effective phase separation.