In order to overcome the problems of large error of traffic data synchronisation and high-traffic congestion rate in traditional methods, a data synchronisation method of intelligent transportation system based on Internet of Vehicles (IoT) technology is proposed. Intelligent transportation system data is extracted using the car networking technology. According to the collected data, to extract the road traffic flow, velocity and density online traffic flow are characteristics. Combined with the data acquisition and traffic flow feature extraction result of intelligent transportation system for scheduling task, according to the result of task scheduling based on training symbol synchronisation method to construct scheduling task timing metric function. The function is used to calculate the data synchronisation estimation points of the intelligent transportation system and realise data synchronisation. The simulation results show that the traffic data synchronisation error rate and traffic congestion rate of the proposed method are low, and the practical application effect is good.