Abstract: Electrochemical hydrogen-charging was applied on 304L austenitic stainless steel plate to study the relations between tensile property of the steel before and after hydrogen-charging and hydrogen contents, the tensile property of pre-charged and hydrogen-releasing of 304L austenitic stainless steel was studied and the characteristic of tensile fracture was analyzed. The results show that plasticity of the stainless steel after hydrogen-charging obviously decreased, and the plasticity decreasing degree increased with the increase of hydrogen contents. When mass fraction of diffusible hydrogen was more than 12×10-6, the elongation decreasing rate was above 10%. The surface fracture characteristics changed from ductile fracture before hydrogen-charging to embrittlement fracture after hydrogen-charging. After hydrogen-releasing, the plasticity could obtain a certain degree of recovery.