Abstract: With the economic development and the improvement of people's living standard,urban traffic congestion is widespread.In order to solve the traffic jam problem,it is necessary to carry out real-time detection of traffic vehicles.In this paper,a real-time traffic vehicle detection system is built firstly.In the system,the magnetic field of the road is detected by an easy-to-install low-cost magnetoresistive sensor HMC5883L;then CC2530 chip receives and processes the data collected by the magnetic sensor HMC5882L through the I2C serial port,and transmits the data to the computer through the UAT serial port.Through the simulation experiment and the actual road experiment,the nature and characteristics of the magnetic signal of the traffic vehicle based on the system are analyzed,which lays a foundation for the actual magnetic signal detection of road traffic vehicles.