With the rapid advancement of aerospace technology, difficult-to-machine materials such as high-strength alloys, ceramics, and composites have gained widespread application. But traditional machining methods struggle to meet the demands for high-quality processing. Waterjet-guided laser processing technology, with its advantages of high precision and low damage, addresses the shortcomings of tool wear and large heat-affected zones inherent in conventional mechanical machining and laser machining, demonstrating significant application potential. Therefore, this paper systematically reviews the working mechanisms and practical applications of waterjet-guided laser processing technology for difficult-to-machine materials in the aerospace field. First, it elaborates on the fundamental principles of waterjet-guided laser processing, the multi-field coupling material removal mechanism, and comprehensively introduces the core components of the waterjetguided processing system. Second, it delves into its multidimensional working mechanisms from three dimensions: water jet characteristics, optical properties, and water-optical coupling characteristics. Subsequently, it comprehensively summarizes research progress in cutting and hole-making processes for “difficult-to-machine materials” using waterjetguided laser technology. Finally, it explores typical application scenarios of this technology in precision machining, based on current research status, and outlines future development trends for waterjet-guided laser precision machining technology.