The　effects　of　gamma　irradiation　on　the　electrical　and　trapping　properties　of　AlGaN/GaN　high-electron-mobility　transistors　(HEMTs)　are　investigated　in　detail.　During　the　irradiation,　the　gate-source　leakage　current　of　the　HEMT　is　monitored　online　when　applying　a　reverse　gate　voltage.　The　variations　of　electrical　properties　of　the　device,　including　an　increase　in　drain-source　current,　the　negative　threshold　voltage　shift,　and　a　decrease　of　leakage　current,　are　observed.　In　particular,　three　traps　in　the　device　are　identified　using　the　voltage-transient　method　and　the　variations　of　these　traps　after　irradiation　are　also　investigated.　The　results　show　that　the　absolute　amplitudes　of　the　three　traps　in　the　device　decrease　after　irradiation,　which　indicates　a　reduction　in　the　density　of　the　traps.　Furthermore,　it　is　proposed　that　the　time　constants　and　energy　levels　of　the　three　traps　decrease　after　irradiation.　The　observed　changes　in　the　trapping　behaviors　are　ascribed　to　the　structural　ordering　of　the　defects,　which　is　consistent　with　the　improvement　in　the　electrical　characteristics　of　the　device.