Taxi is an indispensable component of urban transportation system, which aims to provide a convenient and efficient means of transport. However, unlike bus service that has fixed station and schedule, to most taxi-seekers, the formula for catching a taxi at the nearest place with the shortest waiting time is experience plus luck, especially in peak hour or adverse weather conditions. In this demo paper, we present Taxi-Viewer, a service-oriented online system to help users pinpoint the hot spots where usually have more chances to catch a taxi, and keep users informed of the real-time location and trajectory of taxis in a given neighborhood. With the functions provided in the demo, taxi-seekers can reduce waiting time, and taxi operator can also benefit from the system to improve service quality and increase profit as well.