Abstract: Based on the analysis of the spatial characteristics of traffic information,the paper defines the information degree function which is used to express spatial characteristics of traffic information.The correlation analysis of traffic data is done using the real world data of Second Ring Road in Beijing,then the scattered plots and the mathematical expression of the information degree function are obtained.According to the calibration of information degree function,the spatial distribution of traffic information on the road can be collected,and it can provide references for allocation optimization and networking optimization of road traffic sensors.