Trapping　effects　still　limit　the　application　of　GaN-based　high-electron　mobility　transistors　(HEMTs).　This　paper　further　characters　traps　in　GaN　HEMTs　based　on　the　drain　current　transients.　A　hybrid　transient,　which　contains　more　valuable　information　of　traps　than　the　single　trapping　or　detrapping　transient　was　detected　and　analyzed.　Three　traps　with　different　time　constants　were　determined　and　their　possible　mechanisms　were　discussed.　In　particular,　a　dynamic　capturing　and　releasing　process　during　the　current　transient　was　proposed,　by　which　a　more　appropriate　measured　condition　for　analyzing　current　transients　can　be　acquired.