The　beam-to-column　joint　rotation　influences　the　internal　force　and　deformation　of　steel　frames　as　well　as　the　design　of　the　beam　and　column　members.　The　moment-rotation　(M-φ)　relationship　of　the　beam-to-column　joint　from　the　experiments　or　computer　simulation　is　one　of　the　most　important　parameters　to　study　the　influence　of　the　joint　behavior　on　the　steel　frame.　This　paper　investigates　the　stress　state　and　deformation　of　the　joint　components,　consults　the　theories　of　component　method　from　Eurocode　3,　enumerates　the　definitions　and　mostly　composing　of　the　beam-to-column　joint　rotation　in　steel　frames,　then　compares　the　measuring　and　calculation　method　and　the　joint　mechanical　model　for　the　structural　analysis　of　steel　frames　which　were　proposed　by　different　researchers.　The　research　work　in　this　paper　provides　a　solid　foundation　to　calculate　the　joint　behavior　and　rotation　as　well　as　its　influence　on　the　structural　behavior　of　steel　frames.