The invention relates to an air-to-ground heterogeneous robot system path planning method based on neighborhood constraint. A heterogeneous robot system is formed by at least one ground mobile robot and at least one air flying robot. The method is characterized in that the ground mobile robot and the air flying robot start from a start point at the same time, successively access N sub-task points for executing sub-tasks and finally reach a destination together; and the position of each sub-task is allowed to be effective in a certain neighborhood, and neighborhood constraint is introduced. In addition, the maximum speed constraint is considered respectively for the air flying robot and the ground mobile robot. According to the invention, the air-to-ground heterogeneous robot system is enabled to fully utilize respective characteristics to realize advantage complementation, the tasks are completed in a certain neighborhood range, the efficiency of path planning is improved, the resources are saved, and the air-to-ground heterogeneous robot system path planning method is applicable to the fields such as marine cooperative rapid rescue, target identification and communication networking, cooperative environment sensing and positioning, so that the method has a wide application prospect.