The　improvement　performance　of　refrigerating　dehumidification　system　was　theoretically　discusses　based　on　a　dehumidification　model.　The　influence　of　evaporator　inlet　wind　speed,　dry　bulb　temperature　and　relative　humidity　on　dehumidification　were　analysed　by　the　model.　The　results　show　that,　when　inlet　air　temperature　and　humidity　were　kept　constant,　the　dehumidification　capacity　increased　first　and　then　decreased　with　increase　of　the　wind　speed.　When　the　moisture　content　and　the　wind　speed　of　the　inlet　air　were　kept　constant,　the　dehumidification　capacity　gradually　decreased　with　increase　of　the　inlet　air　dry　bulb　temperature.　The　inlet　air　dry　bulb　temperature　was　between　21-36　degrees　C　and　the　relative　humidity　was　between　40%　and　85%,　the　difference　between　the　inlet　air　wet　bulb　temperature　and　the　evaporation　temperature　at　the　optimum　COP　was　about　10　degrees　C.　There　was　a　nearly　linear　relationship　between　the　corresponding　evaporation　temperature　at　the　optimal　COP　and　the　evaporation　temperature　with　the　maximum　dehumidification　capacity,　compared　with　the　test　value,　the　error　was　less　than　10%.