There　are　two　interesting　phenomena　for　the　electrical　contact　characteristics　of　YBCO　bulk.　One　is　the　transition　between　low　and　high　contact　resistance　states　at　a　threshold　current　value　which　is　called　a　transfer　current;　the　other　is　the　forming　reason　of　the　residual　resistance　when　the　carrying　current　is　lower　than　the　transfer　current.　In　this　paper,　an　axial　symmetric　model　is　constructed　to　investigate　these　two　phenomena.　During　the　calculation,　the　thermal　field,　the　electrical　field　and　the　self　magnetic　field　are　coupled　with　each　other.　The　detailed　fields＇　distributions　are　obtained.　The　calculation　results　are　accordance　with　the　experimental　results.　And　some　useful　conclusions　are　drawn　based　on　the　numerical　analyses.