Study　the　high　temperature　characteristics　of　the　ohmic　contact　of　Ti/Al/Ni/AuC　15　nm/220　nm/40　nm/50　nm)　multiplayer　contacts　to　n-type　GaN(Nd=3.7　×　1017　cm-3,　Nd=3.0　×　1018　cm-3),　the　experiment　shows　that　the　contact　resistivity　keeps　unchanged　and　shows　good　temperature　reliability　when　the　storage　temperature　under　300°C　during　the　storage　time　of　0-24　hours;　but　the　ohmic　contact　has　shown　evident　degeneration　after　the　storage　at　300°C　for　24　hours　and　at　500°C　for　24　hours　respectively.　Furthermore,　the　contact　resisivity　shows　unrecoverable　characteristic.　The　contact　resistivity　will　increase　with　the　measurement　temperature,　and　the　tendency　of　increasing　is　related　to　doping　concentration,　The　higher　the　doping　concentration,　the　slower　of　decreasing　the　contact　resistivity　with　measurement　temperature.　Ti/Al/Ni/Au　ohmic　contact　to　heavy　doping　n-GaN　better　high　temperature　reliability.