This paper focuses on full-ocean-depth multi-channel fiber-optic watertight connectors, providing a comprehensive analysis of their product design, manufacturing processes, testing protocols, sea trials, and scalability. By overcoming a series of critical technological challenges, the research achieves domestic substitution of such connectors, significantly enhancing China’s autonomous capabilities in deep-sea equipment. Extensive sea trials have validated the exceptional performance of the developed connectors, demonstrating substantial socioeconomic benefits and offering robust support for the advancement of China’s marine engineering endeavors.