This　paper　presents　a　detailed　investigation　of　trapping　effect　in　AlGaN/GaN　high-electron-mobility　transistors　based　on　the　pulsed　current-voltage　characterization,　drain　voltage　transient　(DVT)　measurement,　and　capacitance　deep-level　transient　spectroscopy　(C-DLTS).　By　monitoring　the　DVTs　at　various　filling　voltages　and　temperatures,　the　properties　of　three　electron　traps　were　obtained　with　the　DVT　measurements.　Specifically,　the　energy　levels　of　the　former　two　traps　were　determined　to　be　0.28　and　0.48　eV,　which　was　confirmed　by　the　C-DLTS　measurement　performed　on　the　same　device.　In　addition,　a　third　temperature-independent　trap　located　in　the　GaN　buffer　was　observed　only　with　the　DVT　measurement,　indicating　the　advantage　of　transient　curves　measurement　in　characterizing　the　traps　insensitive　to　temperature.　The　combined　measurements　demonstrate　the　correlation　of　different　techniques,　which　allows　identifying　the　same　trap　levels　to　investigate　the　physical　origin　of　traps.