Public bikes rental system is an innovative scheme of rental bicycles in urban areas and can be seen as part of the public transport system. This study investigates the users of Taipei YouBike rental system, analysis their intention and behaviors, pre-expectation and actual experience on satisfaction. The result indicates that the users were mostly from long term annual fee commuters. The result also reveals distinct discrepancies between pre-expectation and actual experience, especially in distributes of safety routes and environments and clear indication of signs on bike routes. The findings can be used for Taipei City to improve the urban bicycle program and make more effort to develop safety cycling infrastructures and amenities.