The　thermal　energy　storage　performance　and　phase　change　stability　of　mix　phase　change　materials　consisted　of　stearic　acid　and　Na2PO4　center　dot　12H(2)O　are　studied　by　means　of　Fourier　transformation　infrared　spectrum　analyses　(FTIR)　and　Differential　Scanning　Calorimetry　(DSC).　The　specific　heat　capacity　of　mix　materials　is　also　determined　experimentally.　The　results　show　that　all　absorption　peaks　of　functional　groups　and　chemical　bonds　of　stearic　acid　still　exist,　which　suggests　that　these　crystal　materials　composed　of　stearic　acid　and　Na2PO4　center　dot　12H(2)O　have　good　phase　change　stability　and　chemical　compatibility.　Thus,　disadvantages　caused　by　the　subcooling　of　Na2PO4　center　dot　12H(2)O　and　the　low　specific　heat　capacity　of　stearic　acid　can　be　solved,　it　is　speculated　that　complement　each　other　on　the　basis　of　organic/inorganic　characteristics　in　itself　is　carried　out　for　these　two　component　materials　of　the　mixture.　(C)　2010　Elsevier　Ltd.　All　rights　reserved.