Ohmic　contact　is　evaluated　under　the　high-current　density,　the　traditional　Transmission　Line　Method　(TLM)　structure　is　innovated,　which　only　age　the　contacts　areas　not　others.　The　new　method　can　ensure　the　reliability　and　validity　when　the　structure　is　applied　high-current　density.　According　to　two　times　or　more　SiO2　deposition,　it　reduces　effectively　the　probability　of　leading　wire　fracture.　The　results　show　after　high-current　density:　the　contact　resistivity　is　rapidly　failure　early　period　and　degenerates　dramatically　with　time　and　current　density.　From　the　spectrum,　Al　is　a　kind　of　low　electromigration　resistance　metal,　the　good　ohmic　contacts　are　destroyed　due　to　electromigration　and　the　Al　is　moved　off　the　contact　layers.　The　experiment　proved　that　it　is　a　perfect　method　after　improving　to　measure　the　ohmic　contact　under　the　high-current　density.