Vehicle　flow　show　continuous　behavior　and　traffic　light　exhibit　discrete　event　behavior,　thus　a　rectangular　hybrid　automata　model　of　a　four-phase　intersection　is　proposed　in　this　paper.　The　queue　lengths　are　considered　as　continuous　variables　to　represent　the　vehicle　flow　behavior　of　the　intersection,　and　the　discrete　event　part　are　used　to　reflect　the　discrete　characteristics　traffic　light.　Based　on　the　rectangular　hybrid　automata　model,　all　directional　vehicle　flows　are　analyzed.　A　method　for　reachability　analysis　of　rectangular　hybrid　automata　is　applied　to　examine　the　maximum　and　minimum　of　each　queue　length　of　the　single　intersection.　The　simulation　based　on　toolbox　CheckMate　3.6　shows　that　the　rectangular　hybrid　automata　model　not　only　perfectly　represents　the　hybrid　characters　of　the　dynamic　traffic　flow　of　the　single　intersection,　but　also　verifies　the　efficiency　of　the　time　scheme　of　the　traffic　light.