The　austenite　homogenization　of　carbidic　austempered　ductile　iron　is　studied　from　both　thermodynamics　and　dynamics　by　calculation　and　experimentation,　and　a　mathematical　model　of　carbide　dissolution　is　established　to　predict　the　dissolved　quantity　of　carbides.　The　results　indicate　that　the　mass　fraction　of　carbon　in　austenite　(austenite-graphite　stable　equilibrium)　calculated　by　the　Thermo-Calc　software　is　similar　to　the　results　quantitatively　analyzed　by　electron　probe.　Based　on　Fick＇s　second　law,　the　elemental　diffusion　kinetics　is　analyzed　by　MATLAB　software.　Because　the　diffusion　rate　of　chromium　in　austenite　is　lower　than　carbon,　the　carbon　content　is　significantly　decreased　around　undissolved　carbides,　but　the　chromium　content　is　still　high.　Two　equations　of　undissolved　carbides＇　area　are　obtained　by　linear　fitting.