The　diffraction　properties　of　two　types　stainless　stain　were　discussed.　To　clarify　whether　the　two　diffraction　peaks　during　the　process　of　2θ　scanning　of　austenite　stainless　steel　diffraction,　can　be　the　basis　of　the　stress　measurement,　two　different　austenite　stainless　steels-0Cr18Ni9　(raw　material),　1Cr18Ni9Ti　(stress　relief　annealing)　and　martensitic　stainless　stain.　(A335P92)　were　measured　for　many　times　in　this　paper.　They　were　demarcated　by　equal　intensity　girder　method　and　detected　by　X-ray　system　and　electromotive　method　respectively　when　gradually　loaded　by　using　a　modified　residual　stress　detecting　equipment,　self-edit　measuring　software　and　based　on　the　monitoring　and　disposing　function　in　spots　during　diffracting　process.　Then　the　X-ray　diffraction　characteristics　were　obtained　by　comparing　with　theoretical　values.　The　results　show　that　austenite　and　martensitic　stainless　steel　reflect　the　different　characteristics　of　the　diffraction.　Although　at　127°,　corresponding　to　crystal　face　(220),　Kα　diffraction　peak　of　austenite　stainless　steel　is　strikingly　marked,　and　two　peak　locations-the　half-width　and　parabola　are　accurate,　the　precision　is　poor　and　the　stress　calculated　from　this　peak　does　not　represent　the　actual　stress　according　to　this　peak.　However,　although　Kβ　diffraction　peak　at　149°,　corresponding　to　crystal　face　(311),　in　spite　of　the　lower　peak-back　ratio,　149°　Kβ　can　be　the　basis　to　calculate　stress　after　the　stress　constant　was　modified.　Martensitic　stainless　steel　shows　the　diffraction　properties　which　are　close　to　that　of　α-Fe,　and　the　difference　between　the　stress　constant　acquired　by　martensitic　stainless　steel　calibration　and　that　of　conventional　α-Fe　is　7.8%.