In hydrogen exposed environment, The mechanical properties of high strength steels, such as tensile strength, elongation and reduction of area, would be degraded by the effect of the hydrogen embrittlement, and the susceptibility of hydrogen embrittlement becomes greater with increasing the strength level of steels. To prevent potential this hazardous elements, A reliable hydrogen embrittlement testing method should be developed and every hydrogen steels have to evaluate how much it affected in hydrogen environment. We have standardized the hydrogen embrittlement testing method as ISO and this standard method provides the evaluation method of the resistance to hydrogen embrittlement using constant loading test with hydrogen pre-charged specimens. The amount of hydrogen content absorbed in the specimens will be analyzed quantitatively by thermal desorption analysis such as gas chromatography, mass spectrometry and so on. For the case of hydrogen continuous charging such as hydrogen absorption in aqueous solution at free corrosion potential, hydrogen absorption in atmospheric corrosion environments and hydrogen absorption in high pressure hydrogen gas, the evaluation method is also briefly described. This method is mainly applicable for the evaluation of hydrogen embrittlement resistance of high strength steel bolts.