Abstract: Aiming at the detection requirements of key components with complex curved surfaces in high-end equipment, and to solve the problems of poor adaptability, numerous scanning blind zones and inflexible path planning of traditional multi-axis C-scan (equal-depth scanning)equipment, an 8-axis linkage robotic arm ultrasonic testing system for complex curved surfaces is developed. The development of three core modules, including hardware system integration, independent C-scan software development and ultrasonic detection algorithm optimization, has been completed, achieving accurate detection of key components with complex curved surfaces. Key breakthroughs are achieved in core technologies including electromechanical cooperative control of multi-axis linkage systems, full-region path planning and profiling scanning technology for complex curved surfaces, autonomous ultrasonic C-scan imaging and control technology, and ultrasonic signal processing algorithms The test results indicate that the system has a complete and reliable hardware structure, and its human-computer interaction and software interface are reasonable and user-friendly. The optimized algorithm is reliable and verified by experimental data to improve the signal-to-noise ratio from 4.4 dB to 18 dB. The system can perform a full scan of all 9 surfaces of complex disk and ring components without any blind zones. It has a stable detection capability for ϕ0.4 mm and ϕ0.8 mm micro flat-bottom holes and transverse holes, with positioning errors less than 1% for both. The detection results have good consistency and high stability. The system has been successfully applied in engineering for internal testing scenarios, realizing the domestic substitution and industrialization of ultrasonic testing equipment for complex components of high-end equipment.