The concept of smart city is very popular recently, because with the development of rail transit, population migration in China has become the largest species migration in the world. With the deepening of population density, it is imperative to develop intelligent transportation. However, when developing smart transportation, it is necessary to establish smart transportation big data. Such a large amount of data may be related to the traffic safety of the whole city, so it must be guaranteed during construction. In terms of the security of smart transportation big data, Dimon gave such suggestions: First, we must be stricter when auditing smart transportation companies to prevent contact with foreign forces, and then do a good job of supervision.