Abstract: For the co-site interference effect on vehicular communication system, a quantitative analysis model is proposed. Firstly, the coupling degree of power is analyzed from experiment and theory, especially the interference suppressed performance of receiver is studied. Then, through analyzing the patterns of the modulation, encoding and interleaving, the computing function library of bit error rate (BER) is established, which is used as a sub block. To verify the accuracy and validity of the quantitative analysis model, a wired experiment platform based on the requirement analysis is established. Study indicates that the theoretical and experimental results are consistent, and this model is the foundation in designing communication system and arranging parameters of radio communication.