Based　on　Deterministic　Finite　Automaton　(DFA)　and　combinational　logic　circuits,　an　implementation　of　a　model　machine　using　Verilog　HDL　and　top-down　method　is　proposed　This　paper　describes　how　to　design　each　of　its　parts　with　the　schema　of　DFA　in　Verilog　HDL　and　simulates　the　machine　in　the　end.