Intelligent and connected vehicles are believed to be the future solution to traffic management, especially in highly challenging areas such as intersections. In this paper, a priority tree based coordination method is proposed for intelligent and connected vehicles at unsignalized intersections. First, a dynamic scheduling method is used to generate the crossing order of the vehicles, considering the conflicting relationship, waiting time, and arrival time of the vehicles. Then a conflict resolution method is presented to handle the spatial and temporal conflicts among the vehicles inside the intersection. And the simulation results show that the method can generate collision-free traffic flows as well as improving the traffic performance.