Combining with the working principle of Intelligent Transport System, and with the purpose of enhancing the security of modern traffic, this paper brings forward a project of building a kind of automobile emergent calling system which starts-up with the starting of airbag, the wireless date transport modem, which is droved by serial interface, transmitted the acquired data to the remote monitoring center. The design of the hardware circuit implement, the design of software and the design of building monitor and control center are demonstrated. And finally, the key technique of the system is also discussed