A　gallium　nitride　(GaN)　high-electron-mobility　transistors　(HEMTs)　operates　in　a　high-frequency　switching　state,　and　its　usage　reliability　is　reduced　when　the　temperature　increases　as　a　result　of　the　increase　of　power　density　and　size　reduction.　To　measure　the　HEMT　temperature　increase　based　on　the　characteristics　of　the　gate-source　structure　of　the　HEMT　device,　this　paper　proposes　the　use　of　reverse　gate　current　as　a　thermo-sensitive　parameter　to　measure　the　temperature　and　improve　the　temperature　characteristics　of　the　parameter　by　reasonably　changing　the　gate　voltage.　A　theoretical　analysis　of　the　reverse　gate　current　components　was　carried　out,　and　the　trends　and　changes　in　its　temperature　characteristics　were　investigated.　The　influencing　factors　affecting　the　reverse　gate　current　were　discussed,　and　the　phenomenon　of　the　current＇s　sudden　change　with　temperature　was　explained.　©　2019　IOP　Publishing　Ltd.　All　rights　reserved.