The　high　temperature　characteristics　of　the　ohmic　contact　of　Ti/Al/Ni/Au　(15　nm/220　nm/40　nm/50　nm)　multilayer　contacts　to　n-type　GaN(Nd=3.7　×　1017　cm-3,　Nd=3.0　×　1018　cm-3)　are　studied.　The　annealed　samples　still　show　excellent　ohmic　contact　characteristics　at　500°C.　Contact　resistivity　increases　with　the　rise　of　temperature.　Furthermore,　the　tendency　of　increase　is　related　to　doping　concentration:　The　higher　the　doping　concentration,　the　slower　the　increase　of　the　contact　resistivity　with　the　temperature.　Ti/Al/Ni/Au　ohmic　contact　to　heavy　doping　n-GaN　has　better　high　temperature　reliability.　The　contact　resistivity　shows　unrecoverable　characteristics　after　the　samples　are　placed　under　the　thermal　stress.