Urban　transportation　systems　are　very　complicated　systems,　which　present　a　lot　of　problems　on　modeling.　This　paper　gives　an　overview　of　traffic　models,　points　out　the　strongpoint　and　shortcomings　of　the　macro-　and　micro-　models,　analyses　reasons　for　hybrid　system　modeling　of　urban　traffic.　This　paper　will　give　the　reasons　and　an　overview　of　the　hybrid　system　modeling　of　urban　transportation　systems.