The　Active　Sound　Enhancement　(ASE)　System　in　electric　vehicles　plays　a　crucial　role　in　con-structing　diverse　sound　features　and　enhancing　driving　control　perception.　For　the　ASE　technology　for　electric　vehicles,　a　variable-weight　multimodal　switching　sound　synthesis　algorithm　is　proposed　in　this　paper.　By　constructing　a　mode-switching　factor　matrix,　it　organically　combines　order　synthesis,　pitch　modulation　synthesis,　and　particle　synthesis　methods　to　form　a　deep　sound　fusion　ASE　System　to　achieve　real-time　synthesis　of　multimodal　in-cabin　sound　profiles　aimed　at　enriching　subjective　auditory　perception,　increasing　the　richness　of　the　ASE　System,　and　making　the　synthesized　sound　more　three-dimensional　and　saturated,　thus　enhancing　the　driving　experience.　Subsequently,　a　sound　modulation　Software　for　electric　vehicles　is　developed　using　C#,　integrating　ASE　System　control　and　sound　modulation　function　to　realize　quick　and　flexible　modulation　of　vehicle　sound.　Finally,　the　application　of　the　sound　modulation　Software　in　the　sound　modulation　of　a　specific　pure　electric　SUV　is　demonstrated.　Sound　tests　combined　with　subjective　evaluation　results　indicate　that　this　Software　can　effectively　achieve　multimodal　sound　synthesis　goals,　offering　practical　engineering　application　value.　©　2025　SAE-China.　All　rights　reserved.