In　this　paper,　we　consider　a　single　intersection　of　four　phases.　A　new　time-planning　scheme　is　put　forward,　based　on　the　model　of　hybrid　automata　for　the　intersection.　We　introduce　the　optimization　of　hybrid　systems,　and　use　the　average　queue　length　over　all　queues　as　objective　function　to　find　an　optimal　traffic　light　switching　schemes.　The　novel　method　is　only　a　primary　try,　and　the　further　actual.　schemes　are　brought　forth　in　the　future.