An air-ground joint trajectory planning and offloading scheduling method and system for distributed multiple objectives is provided. At the beginning of each timeslot, an unmanned aerial vehicle (UAV) selects a flight direction based on a total energy consumption of all devices and a total amount of unprocessed data of all the devices in the current system, and flies a fixed distance towards a certain direction. Before the UAV reaches a new location, each terrestrial user independently selects a task data offloading scheduling strategy based on the total energy consumption of all the devices and the total amount of the unprocessed data of all the devices in the current system. In order to improve an expected long-term average energy efficiency and data processing capability, the present disclosure also provides average feedbacks for an energy consumption and unprocessed data.