A　coupled　global　model　of　fluid　flow　and　heat　transfer　was　developed　for　a　cold　store　in　use.　The　convective　heat　transfer　in　the　springhouse,　the　jet　flow　of　the　air　curtain　installed　at　the　entrance　and　the　environmental　flow　outside　the　cold　store　were　solved　together　in　a　coupled　way.　The　effects　of　the　outlet　width,　the　jet　velocity　and　the　jet　angle　of　the　air　curtain　on　its　performance　and　efficiency　were　numerically　studied　respectively　under　the　condition　that　the　air　curtain　and　store　gate　opened　simultaneously.　The　results　showed　that　there　existed　an　optimal　value　for　the　jet　velocity　and　the　jet　angle　at　which　the　air　curtain　had　the　best　performance　and　the　highest　efficiency.　A　large　outlet　width　does　not　necessitate　for　better　performance　of　an　air　curtain　if　it　exceeds　the　critical　value.