<p>Repairing failed metal parts is crucial for promoting green and sustainable development. The traditional repair mode of separate additive and subtractive processes requires the coordinated operation of multiple devices. This causes low efficiency, poor positioning accuracy, and difficulty in addressing potential macroscopic defects such as humping, lack of fusion, delamination, and side collapse during material deposition. Therefore, this paper proposes a hybrid repair method that integrates additive and subtractive processes on a single device to solve these challenges. Additionally, in response to the problems of low rigidity and poor milling stability in the robot hybrid additive and subtractive system, we developed a serial-parallel structure enhanced robot hybrid wire arc additive manufacturing (WAAM) and milling processing system. This system, designed for quickly repairing damaged parts, has high rigidity, excellent milling stability, a large working space, high repair efficiency, and high precision. These benefits come from the robot's unique structure. The serial-parallel mechanical structure boosts the robot's rigidity and milling stability. The hybrid additive and subtractive repair process cuts down on part disassembly, clamping, and positioning of parts, improving the repeat positioning accuracy and repair precision. Furthermore, the interlayer milling effectively eliminates potential macroscopic defects during the material deposition process. This paper details about the structural design, performance verification, control system development, auxiliary system integration, and implementation of the hybrid additive-subtractive repair method for the robot repair platform.</p>