Based　on　the　analysis　of　longitudinal　control　scenarios,　a　longitudinal　control　model　of　the　intelligent　vehicle　in　virtue　of　hybrid　automata　is　built.　Driving　situations　are　divided　into　cruise　control,　speed　following,　inter-vehicle　distance　adjustment　modes.　Three　corresponding　control　strategies　are　proposed　depending　on　the　driving　modes.　Then　an　algorithm　of　the　longitudinal　controller　is　designed.　Not　only　is　the　following　control　of　the　target　vehicle　in　the　same　lane　achieved,　but　also,　when　the　target　vehicle　changed,　the　following　control　of　the　new　target　vehicle　is　achieved　through　the　control　strategies　of　inter　vehicle　distance　adjustment.　Simulation　results　show　that　the　designed　strategy　can　achieve　a　variety　of　scenarios　in　both　highspeed　driving　and　low-speed　stop-and-go　situations.