A　three-dimensional　cellular　automaton　(CA)　model　is　applied　to　simulate　isothermal　crystallization　of　monomer　casting　(MC)　nylon　6.　The　kinetics　is　formulated　based　on　the　Kim　and　Kim＇s　rate　theory　for　spherulite　expansion.　The　probability　of　distribution　of　crystalline　nuclei　and　impinging　were　determined　by　Monte　Carlo　method.　The　spherulite　impinging　was　considered　in　the　simulation　through　the　deduction　of　overlay　of　spherulite　volume.　The　number　of　spherulite　nuclei　and　bulk　density　of　MC　nylon　6　after　completing　crystallization,　easily　obtained　from　experiment,　were　used　as　input　data,　allowing　one　to　make　predictions　on　a　real　time　and　space　scale.　Finally,　the　model　was　verified　by　quantitative　comparison　between　the　simulation　results　in　this　work　and　experimental　data　in　literatures.　©　2008　Elsevier　Ltd.　All　rights　reserved.