In order to solve the network data structure layer distribution of traditional urban transportation, the data upload and independent management of each organization cannot realize information sharing, and there is the problem of information islands. This article proposes the blockchain technology that has been developing and gradually mature in recent years, and builds an intelligent big data platform for urban traffic based on blockchain technology. Based on block data, the centralized data management of different data organizations will be removed, and the methods of data collection, processing, and storage will be completely changed, so as to realize big data sharing, decentralization and distributed computing of the intelligent transportation diversified system platform. Based on the blockchain technology urban intelligent transportation big data platform, the different problems that need to be solved and faced is to unify the data of different data sources, realize the unified supervision and operation of the data, and achieve advanced counting compatibility. It is found that the traditional traffic data network architecture can be solved under the blockchain-based traffic big data architecture, which is limited by the installation layout and subordinate management of the equipment, and the data road network coverage depends on the objective environment. The application of blockchain transportation big data is obtained, which can successfully break through the limitations of organizations, share urban intelligent transportation data, and solve the problem of data missing.