Abstract: Cellular-vehicle-to-everything side link interface (PC5) adopts the form of device to device direct communication, which has the characteristics of low communication delay, large transmission capacity and high transmission reliability, and has broad scientific research and engineering prospects. In order to measure the characteristics of the side link channel of the cellular vehicle-to-everything, a vehicle-mounted board with PC5 interface is used for communication measurement on urban roads. Based on the measurement results, the communication channel of PC5 interface is analyzed from the channel characteristics. The characteristics of packet receiving delay varying with distance and signal-to-noise ratio are analyzed. The measured reference signal receiving power value is compared with the predicted values of the two path loss empirical models of free space and double ray and the two path loss fitting models of logarithmic distance and double slope. Four correlation analysis algorithms are introduced to analyze the correlation between the predicted value of the model and the measured data from the degree of linear correlation and the similarity of geometric morphology. It is verified that the dual-slope path loss model is most suitable for characterizing the fading characteristics of the PC5 interface channel in the urban environment. The path loss index and shadow fading variance calculated based on the model can better characterize the channel characteristics in combination with the experimental environment.