The　experimental　system　of　household　air-source　heat　pump　water　heater　with　flash　tank　was　set　up,　and　its　operation　performance　at　different　temperatures　was　studied　in　the　environmental　control　room,　and　compared　with　the　single-stage　compression　system.　The　results　show　that　the　heating　capacity　and　heating　COP　of　the　household　air-source　heat　pump　water　heater　with　flash　tank　are　greater　than　that　of　the　single-stage　compression　system,　and　the　heating　capacity　increases　21.　3%　when　the　ambient　temperature　is　-15　℃.　The　heating　time　of　air-source　heat　pump　water　heater　with　flash　tank　system　is　shortened　by　20.　1%　compared　with　that　of　single-stage　system　under　the　same　water　volume　and　initial　and　ending　temperatures.　The　discharge　temperature　of　the　compressor　is　reduced　by　11.　3　℃,　which　ensures　the　operation　safety　of　the　unit.　The　calculation　of　APF　shows　that　the　system　of　flash　tank　replenishment　is　better　in　the　area　with　lower　ambient　temperature.　©　2022　Authors.　All　rights　reserved.