The　error　distribution　between　Miedema-calculated　values　and　reference-reported　values　for　formation　enthalpies　of　binary　Al-RE　intermetallics　was　analyzed　and　it　is　known　that　the　calculated　results　are　commonly　negative　compared　with　those　in　references.　Therefore,　an　important　influencing　factor,　radius　ratio　of　RE　atom　to　aluminum　atom　should　be　considered　to　modify　the　thermodynamic　calculation　model　in　the　study.　The　calculation　results　of　the　modified　model　are　more　closed　to　the　reported　experiment　results　and　the　error　was　found　to　be　reduced　from　33.6%　to　5%.　The　enthalpies　of　some　common　intermetallics　of　aluminum　and　rare　earth　were　also　checked　by　MTDATA　for　comparison.　All　that　proved　the　modified　calculating　model　are　much　more　accurate　and　reliable.　The　common　formation　enthalpies　of　intermetallics　of　aluminum　and　rare　earth　as　well　as　Al-Er,　Al-Tb,　Al-Gd,　which　are　studied　less,　are　calculated　by　the　modified　Miedema　model.