For　the　scope　of　commercial　supermarkets,　the　demand　for　energy　efficiency　improvement　and　environmentallyfriendly　working　fluid　of　the　refrigeration　system　is　necessary.　In　this　study,　supermarket　booster　refrigeration　system　by　using　eco-friendly　working　fluid　CO　2　/halogenated　alkene　(HA)　mixture　is　proposed,　and　the　mixture　used　in　systems　with　two　evaporation　temperatures　and　operating　modes　affected　by　ambient　temperature　are　studied.　The　energy　efficiency,　economic　performance　and　emission　reduction　potential　of　the　whole　life　cycle　are　conducted　to　compare　with　the　pure　CO　2　booster　refrigeration　system.　Furthermore,　the　influence　of　climate　condition　is　discussed　when　used　in　40　typical　cities　around　the　world.　The　results　show　the　coefficient　of　performance　(COP)　of　booster　refrigeration　system　can　be　significantly　improved　by　using　CO　2　/HA　mixtures.　As　the　ambient　temperature　is　33　degrees　C,　the　CO　2　/R1234yf　(93/7)　operates　with　the　maximum　COP　of　1.367,　which　is　11.59　%　higher　than　that　of　pure　CO　2　.　Using　CO　2　/HA　mixtures　in　the　booster　refrigeration　system　can　significantly　improve　the　exergy　efficiency　of　system.　Moreover,　the　system　using　CO　2　/HA　mixtures　has　higher　annual　performance　factor　and　lower　life　cycle　cost　(LCC)　than　pure　CO　2　.　LCC　of　the　system　using　CO　2　/R1234yf　(94/6)　is　the　lowest,　and　the　reduction　rate　is　3.06　-　5.59　%.　Meanwhile,　the　life　cycle　carbon　emissions　of　systems　in　different　climatic　regions　using　CO　2　/R1234yf　can　be　reduced　by　2.39　-　5.21　%.　The　booster　refrigeration　system　adopting　CO　2　/HA　mixtures　is　a　promising　alternative　solution　for　commercial　supermarket　refrigeration　and　energy　-saving.