The　intermittent　and　instability　problem　of　solar　energy　is　solved　by　using　＂three-phase　accu-mulator　＂　with　the　medium　of　LiBr-H2O　instead　of　the　auxiliary　heater　in　a　solar　air　conditioning　(SAC)　system　based　on　independent-developed　solar　parabolic　trough　collectors　(PTC),　in　which,　＂three-phase　＂　refers　to　LiBr　solution,　LiBr　crystal　and　vapor.　The　multi-objective　optimization　is　conducted　based　on　the　energy　and　economy　analysis.　Pareto　frontier　for　the　multi-objective　optimization　has　been　obtained　with　NSGA　II.　The　optimal　points　have　been　selected　by　LIN　-MAP　and　TOPSIS　decision-making　methods.　The　multi-objective　optimization　results　show　that　the　solar　fraction,　the　energy　storage　density　and　the　system　efficiency　of　the　SAC　system　with　TOPSIS　are　89.67%,　624.67　kWh/m(3),　0.833,　respectively,　compared　with　LINMAP,　which　are　88.31%,　604.22　kWh/m(3),　0.848.　Based　on　the　TOPSIS　decision-making　results,　the　annual　average　investment　of　the　SAC　system　is　161,100RMBY,　the　economic　indexes　of　the　system,　i.e.,　AFC　(annual　cash　flow),　PBP　(payback　period),　NPV(net　present　value)　and　IRR　(internal　rate　of　return)　are　38,100RMBY,　5.53　years,　140,500RMBY　and　7.82%,　respectively.　In　addition,　the　economic　sensitivity　analysis　results　show　that　the　prices　of　PTCs　and　refrigeration　equipment　have　a　greater　impact　on　the　economic　index.