External energy field assisted friction stir welding (FSW) is an improved solid-phase welding method that is widely used in aerospace, automotive manufacturing, and energy industries. By introducing external energy, the microstructure and properties of the joint can be improved, thereby enhancing the welding quality and efficiency. This article classifies external energy field-assisted FSW techniques, summarizes the selection and control of energy fields, optimization of process parameters, and summarizes the effects of external energy fields on welding temperature, axial load, and joint microstructure and properties. Finally, this article summarizes the future development trends of external energy field-assisted FSW technology.