Application For high, middle, low pressure boiler and pressure purpose 15CrMoG alloy tube of the principles of the purified hydrogen at 300-500 ℃, the hydrogen to be purified is passed through one side of the 15CrMoG alloy tube, the hydrogen is adsorbed on 15CrMoG alloy wall, palladium 4d electron shell lacks two electronics, it can with the hydrogen generating unstable chemical bonds (palladium and hydrogen, this reaction is reversible), palladium, hydrogen is ionized proton whose radius is 1.5 × 1015m, while the lattice constant of palladium 3.88x 10-10M (20 ° C time), it can be through 15CrMoG alloy tube role of palladium proton combined with electronic and re-formation of the hydrogen molecules to escape from the other side of the 15CrMoG alloy tube.