Car Data Chain is a new ecosystem-based automotive service platform developed using blockchain technology. It integrates blockchain into the automotive industrys transaction scenarios, circulation scenarios, and service scenarios. It chains a series of information about vehicles from production, sales, maintenance, to repairs for on-chain storage. Blockchain technology establishes a trust system based on machines rather than agreements. A decentralized system composed of technologies such as smart contracts and distributed databases makes the automotive service industry more transparent, authoritative, and fair. On the Car Data Chain platform, automobile manufacturers, dealerships, car trading markets, auto finance companies, leasing companies, insurance firms, and banks can all join the platform to form a comprehensive automotive service system, providing users with high-quality solutions.