With　the　development　of　microgrid　technology,　short-circuit　fault　detection　and　location　research　has　become　a　key　link　in　the　development　of　microgrid　technology.　In　view　of　the　limitation　that　the　existing　short-circuit　fault　protection　schemes　of　micro　grid　do　not　consider　the　change　of　topology　structure　during　the　operation　of　micro　grid,　this　paper　simulates　the　short-circuit　fault　operation　state　of　grid-connected　AC　microgrid　considering　the　change　of　topology　structure,　and　analyzes　it　by　using　the　wavelet　energy　spectrum　change　method,　proposes　a　short-circuit　fault　protection　method　that　can　adapt　to　the　change　of　topology　structure.　©　2023　IEEE.