Abstract: The Portland\|Milwaukee light rail transit is supposed to be a new paradigm of urban rail transit design in the United States, the main embodiment of which in promoting urban vitality lies in the effective connections that have brought an economic vitality to the cities. The light rail stations, along with the station areas offer comfortable and convenient places to get citizens involved in communication, which considerably boosted a social vitality to the cities. A high attention paid to the injection of public participation and community spirit enhanced a cultural vitality to the cities. The construction of light rail transit integrates well with domains like urban planning, landscape design and environment art, improves the scenery along the lines and strengthens the ecological infrastructure, all these have increased the environmental vitality of the cities.