Auto insurance，especially the commercial third-party liability insurance for motor vehicles，plays an important role in ensuring the victims of traffic accidents receive compensation according to law and promote traffic safety. Using the insurance big data from CIITC to track and analyze the national coverage of traffic accident liability insurance，we can objectively evaluate the status of China's traffic accident liability insurance coverage，comprehensively grasp the development trend of traffic accident liability insurance，timely discover problems in various regions，and provide suggestions for the insurance company's business behavior and consumer's insurance behavior.