The　valence　electron　structure　of　Al3M　(M=Ti,　Zr,　Hf)　with　three　crystal　structures　(L1(2),　D0(22),　D0(23))　and　the　corresponding　strongest　bond　energy　(E-A)　values　have　been　calculated　from　the　empirical　electron　theory　(EET)　of　solids　and　molecules.　Based　on　the　calculated　E-A,　the　stability　of　the　phases　with　different　structures　and　the　sequence　of　phase　transition　have　been　analyzed　semi-quantitatively.　The　results　showed　that,　the　E-A　of　the　equilibrium　phases,　i.e.,　D0(22)-Al3Ti,　D0(23)-Al3Zr　and　D0(22)-Al3Hf,　were　57.7,　71.6　and　75.6　kJ/mol,　respectively,　which　showed　the　same　trend　in　magnitude　with　the　corresponding　melting　point.　This　consistence　supports　the　reliability　of　EET-based　calculation　results.　Similarly,　the　E-A　of　Al3Ti,　Al3Zr　and　Al3Hf　with　three　structures　have　been　calculated　and　the　calculated　phase　transition　sequences　are　the　same　as　the　experimental　results　and　those　from　first-principles　calculation.　The　L1(2)-type　metastable　phases　of　three　intermetallic　compounds　exhibit　many　excellent　characteristics,　whereas　their　phase　stability　is　crucial　for　application.　The　E-A　is　supposed　to　be　a　measure　for　the　stability　of　metastable　phase.　The　calculated　E-A　of　L1(2)　structure　implied　the　phase　stability　in　the　order　of　Al3Ti＜Al3Zr＜Al3Hf,　which　was　the　same　as　that　from　the　transition　temperatures　experimentally.　The　E-A　calculated　by　EET,　therefore,　could　be　a　good　measure　for　the　stability　of　metastable　phase.