Stress　corrosion　test　of　pressure　vessels　and　piping　in　H2S　environment　has　been　explored　extensively,　but　experimental　research　closed　to　the　actual　stress　state　of　pipelines　and　the　actual　operating　conditions,　especially　considered　the　combined　effect　of　various　factors　is　not　common.　Stress　corrosion　test　simulated　the　actual　operating　conditions　is　taken　in　this　paper.　Four　in-service　pipes　are　researched　as　specimens　and　complex　stress　field　is　built　by　a　specially　designed　loading　device.　Specimens　are　immersed　in　three　different　H2S　concentration　environments.　The　appearance　and　expansion　of　crack　is　observed　regularly　and　the　sensitivity　of　pipeline　on　stress　corrosion　is　evaluated　by　metallographic　examination.　The　result　shows　that:　Intergranular　corrosion,　transgrantilar　corrosion　or　micro-crack　is　not　found　in　H2S　corrosive　solution　(500x10(-6),　800x10(-6)mg/L)　after　2160　hours　or　in　saturated　H2S　corrosive　solution　(greater　than　2000x10(-6)mg/L)　after　360　hours.　A　surface　crack　is　found　in　H2S　corrosive　solution　(500x10(-6)mg/L)　after　720　hours　and　the　expression　for　expansion　rate　of　the　crack　during　2160　hours　is　a=16.835e(0.0002h).