The invention relates to a vehicle trajectory clustering method based on graph theory. Firstly, the vehicle networking data is obtained, and the massive vehicle trajectory data is cleaned by using a Spark platform. Secondly, the coordinate points are projected onto the map, and the connected graph is formed according to the set K value and the relative approximation through the relative distance relation of the coordinate points, and then the clusters whose connectivity strength is greater than the preset value are merged by using the interconnectivity; finally, the real taxi trajectory data are analyzed to get the traffic flow of different time periods and different areas, that is, the optimal taxi-hailing scheme is given. The invention can effectively improve the speed and quality of data processing.