A　model　of　the　three-stage　integrated　system　consisting　of　a　solid　oxide　fuel　cell,　an　alkali　metal　thermal　electric　converter,　and　an　absorption　refrigerator　is　proposed,　where　the　main　irreversible　losses　are　considered.　Based　on　the　respective　parameter　relations　of　three　subsystems,　the　power　output　and　efficiency　of　the　integrated　system　are　analytically　derived.　The　influences　of　the　current　densities　of　the　fuel　cell　and　the　converter,　electrolyte　thickness　and　temperature　in　the　low-temperature　side　of　the　converter,　and　area　ratio　of　the　converter　to　the　fuel　cell　on　the　systemic　performance　are　discussed.　The　maximum　power　output　density　and　optimally　working　regions　of　the　integrated　system　are　determined.　The　main　novelties　are　to　provide　the　optimum　selective　criteria　of　some　vital　parameters.　It　is　expounded　that　the　results　obtained　from　the　present　model　may　be　directly　used　to　derive　the　optimum　performances　of　the　coupled　system　only　comprised　of　both　the　fuel　cell　and　the　converter.　It　is　found　that　the　maximum　power　output　density　of　the　integrated　system　increase　about　15.8%　and　79.8%,　compared　with　that　of　the　coupled　system　and　the　solid　oxide　fuel　cell,　respectively.