Thermal　analysis　and　sessile　drop　method　were　adopted　to　analyze　the　solidification　process　of　Fe-C-Si　alloy.　The　influence　of　the　undercooling,　the　recalescence　temperature　difference　of　primary　graphite　nucleation,　and　the　liquid-solid　interface　energy　on　the　growth　morphology　of　graphite　in　the　process　of　solidification　of　Fe-C-Si　alloy　were　investigated.　The　results　show　that　the　solidification　characteristic　of　the　graphite　spheroidizing　with　Ce　addition　is　characterized　by　the　significant　reduction　in　the　nucleation　temperature.　However,　even　giving　a　small　undercooling　to　the　alloy　with　the　Ce　addition,　the　graphite　morphology　changed　from　sphericity　to　flake.　This　transformation　is　totally　dependent　on　the　degree　of　undercooling　in　the　crystallization.　So　the　nodulizer　is　not　sufficient　condition　of　graphite　spheroidization,　but　undercooling　is　a　primary　factor　that　promotes　the　spheroidization　of　graphite　during　the　solidification.　The　solidification　curves　also　show　that　the　recalescence　temperature　difference　of　flaky　graphite　is　higher　than　that　of　spherical　graphite,　which　reflects　the　growth　speed　of　graphite,　namely,　the　speed　of　flaky　graphite　is　faster　than　that　of　spheroidal　graphite.　The　liquid-solid　interface　energy　on　the　(0001)　surface　is　higher　than　that　of　(10T0)　surface,　so　the　former　growth　morphology　of　graphite　is　spheroidal,　the　latter　is　flaky.