With　the　development　of　renewable　energy,　hydrogen　energy　is　paid　more　and　more　attention.　Hydrogen　is　an　excellent　energy　carrier,　but　it　is　difficult　to　store　and　transport　because　of　its　special　properties.　Hydrogen　blended　with　nature　gas　is　considered　to　be　one　of　best　transition　solutions　to　solve　the　problem　of　large-scale　hydrogen　transportation.　But　hydrogen　embrittlement　occurs　when　the　pipeline　steel　used　to　transport　natural　gas　is　exposed　to　hydrogen　environment.　Referencing　to　ASME　B31.12,　X42　pipeline　steel　is　selected　as　the　research　object　in　this　paper.　And　the　mechanical　properties　of　X42　were　tested　by　electrochemical　hydrogen　charging,　slow　strain　rate　tensile　(SSRT)　test　and　fatigue　crack　growth　(FCG)　test　combined　with　thermal　desorption　spectroscopy　(TDS)　and　SEM.　Hydrogen　adsorption　properties　of　X42　pipeline　steel　at　room　temperature　was　measured　by　TDS.　SSRT　test　showed　that　the　strength　of　X42　strengthened　slightly　in　electrochemical　hydrogen　charging　environment,　but　the　plasticity　decreased　significantly,　and　the　embrittlement　degree　of　materials　increased　with　the　elevated　current　density.　FCG　test　showed　that　the　presence　of　hydrogen　will　accelerate　the　crack　growth　rate　and　reduce　the　fatigue　life　of　materials.　SEM　images　of　tensile　and　fatigue　specimens　showed　that　hydrogen　transforms　the　fracture　mode　from　ductile　fracture　to　cleavage　fracture.　©　2020　ASME