The　nucleation　of　ammonium　tetramolybdate　in　supersaturated　solutions　prepared　by　HCl　and　HNO3　was　studied　respectively　under　temperatures　from　295.15　K　to　311.15　K　at　different　levels　of　supersaturation.　Effects　of　temperature　and　supersaturation　on　the　induction　period　of　ammonium　tetramolybdate　were　discussed.　According　to　classical　nucleation　theory,　it　was　possible　to　distinguish　the　homogeneous　and　heterogeneous　nucleation　from　the　influence　of　temperature　and　supersaturation　on　induction,　period.　The　interfacial　tension,　critical　radius　and　critical　Gibbs　free　energy　of　formation　of　the　crystal　nuclei　were　estimated.　Differences　of　homogeneous　nucleation　rate　of　ammonium　tetramolybdate　in　solutions　prepared　by　HCl　and　HNO3　were　discussed.