The principle and frame and result of a new kind of parameters detection system are introduced.This system uses magnetic sensor as detection element instead of traditional underground winding and uses single chip processor as the center of the signal disposal circuit.Total number and rates of the vehicles on road can be measured by the system and it can take pictures of the vehicles which over speeding or getting into red light.It can timely transfer all the information to the control center.The test result shows that this system reaches the precision of 98 % about vehicle amount and vehicle rate.It is better than the traditional system and is more convenient to use.