Abstract: The diaphragms used in the electrolyser for hydrogen preparation were briefly introduced.PPS and ES fibers were chosen by experiments,two kinds of diaphragms were developed with these fibers by needle punching and thermal calendaring.Their general performances were tested,and electrolyzing tests were carried out with asbestos diaphragm as a comparison.The results showed that in the electrolyte,the diaphragm made of asbestos has maximal ionic resistance,ES diaphragm has minimal,but it can not be used in hot alkali electrolyte for its poor heat-stability.PPS diaphragm can replace asbestos diaphragm for its good temperature-resistant,anti-corrosion and smaller ionic resistance.