A collaborative optimization control method based on conflict right-of-way decision-making and driving risk field was proposed to address the problem of efficient and safe access of vehicles at unsignalized intersections in unmanned transportation systems of a mine. Firstly, a vehicle conflict state detection model was established by introducing safety margin information, and a three-level right-of-way system of first-come and first-leave, load priority, and priority right-of-way decision library was constructed. Secondly, based on the characteristics of mine working conditions, a driving risk field was established as the safety optimization basis for collaborative optimization control of unsignalized intersections. Finally, by integrating environmental factors, an optimization objective function was established with minimizing traffic risk as the primary objective and traffic efficiency as the secondary objective. A validation scenario for open-pit mine transportation was designed, which includes multiple conflict situations, to verify the collaborative control method. The simulation results show that the collaborative control method can achieve the coordinated and orderly passage of multiple vehicles through unsignalized intersections without stopping, while maintaining the minimum safe distance. The research results can provide a safe and efficient access plan for unsignalized intersections in unmanned transportation systems of smart mines.