The paper introduces the experiment of traffic information service based on probe car system in Beijing of China. It is sponsored by JETRO of Japan, for the protection of environment like deceasing energy consuming and air pollution. About 2000 taxies running on roads send GPS and other status data in real time to the data base of the taxi dispatching center, which transmits the data to the data base in the traffic information center via Internet. In the traffic information center, the probe information system matches the location of taxies on the digital map, calculates the average running speed and travel time on road links, and distributes the traffic information to users every five minutes through FM radio. Based on the information, users can plan the trip before driving based on the instruction of on-board navigator embedded with FM decoder, or drive the destination with its dynamic instruction