Abstract：At present, national economy is developed at a high speed, the following problem of city traffic of our country is serious day by day too, the traditional control mode can not already meet the demand for the contemporary urban traffic control system, there must be a kind of more rational and more simple and more convenient urban traffic control system and appear, so as to ensure the urban road is safe and smooth. And the urban traffic control system based on PROFIBUS is exactly this system. This text has introduced several kinds of more popular on-the-spot bus and characteristic at first, among them has introduced the characteristic of PROFIBUS and development prospect especially, and has explained the meaning of a subject and development trend; then has designed the hardware, provide the topological structure chart, has elected the necessary hardware part and introduced its function in detail , still provide the light hardware wiring diagram of the traffic and hardware disposition form; use the growth curve in the communication network scheme of PROFIBUS network and communication principle, have introduced the agreement structure of PROFIBUS and store the agreement, explain structure, system behavior, data communication and expanded function of the hardwood,etc. in detail ; detail the system finally and work in the way, and design the systematic main program.
