In　present　study,　an　experimental　system　for　circulatory　flash　evaporation　was　designed　and　built.　Energy　and　exergy　analyses　of　circulatory　flash　process　were　carried　out.　Basing　on　the　first　law　of　thermodynamics,　the　gained　output　ratio　of　circulatory　flash　evaporation　(GOR(CFE))　was　defined　as　an　energy　ratio　between　latent　heat　carried　away　by　flash　steam　and　input　excess　energy　of　working　fluids.　The　performance　ratio　of　circulatory　flash　evaporation　(PRCFE)　was　defined　as　the　mass　flow　rate　divided　by　exergy　destruction　rate.　The　Effects　of　main　factors,　namely,　superheat　degree,　circulating　flow　rates,　equilibrium　pressure,　initial　water　level　and　salinity　on　GOR(CFE)　and　PRCFE　were　studied.　Results　suggested　that　GOR(CFE)　decreased　rapidly　at　the　initial　stage,　then　increased　with　the　increase　of　superheat　degree　and　became　flat　eventually.　The　optimal　superheat　degree　was　determined　wherein　the　maximum　performance　ratio　was　reached.　According　to　the　comparison　of　gained　output　ratio　and　performance　ratio,　the　maximum　performance　ratio　was　obtained　when　gained　output　ratio　was　great　enough　and　temperature　difference　was　minimal.