The　packaging　insulation　of　power　electronics　faces　the　dual　challenges　of　high-frequency　pulse　width　modulation　voltage　and　high　operating　temperature,　and　its　degradation　performance　urgently　needs　further　research.　This　article　investigates　the　electrical　tree　growth　characteristics　of　epoxy　resin　under　the　action　of　high-temperature　and　high-frequency　square　wave　pulses　through　methods　such　as　electrical　tree　aging　and　physicochemical　analysis　experiments.　The　results　indicate　that　as　the　frequency　increases,　the　growth　rate　of　electrical　tree　does　not　increase　monotonically,　primarily　due　to　the　influence　of　tree　channel　carbonization　and　space　charge　effects.　There　are　significant　differences　in　the　growth　mechanism　of　the　epoxy　resin　electrical　tree　under　different　temperature　and　frequency　coupling　effects.　At　low　frequencies,　as　the　temperature　increases,　the　morphology　of　the　electrical　tree　changes　from　dendritic　to　clustered,　and　the　growth　rate　of　the　electrical　tree　significantly　decreases.　At　medium　and　high　frequencies,　its　growth　rate　significantly　increases,　and　under　the　coupling　effect　of　high　temperature　and　high　frequency,　a　large　region　of　bubble-like　carbonization　area　is　generated.　The　relevant　work　lays　a　theoretical　foundation　for　the　insulation　design　and　condition　evaluation　of　power　electronic　packaging　under　high-frequency　and　high-temperature　conditions.　©　Authors　2025.