Deep-sea exploration is a key technology for developing marine resources, studying the evolution of the Earth, and protecting the Earth's ecosystem. This paper reviews the main progress of deep-sea exploration technology in the past seven years (2019–2025), including the fields of submersibles, sensors, communication, energy, etc., and looks ahead to the development trends in the next 5~10 years. Firstly, the importance and challenges of deep-sea exploration are introduced. Then, the current status of technologies in various aspects such as deep-sea submersibles, sensors and observations, sampling and analysis, communication and navigation, energy, as well as big data and artificial intelligence are described in detail. The analysis shows that intelligentization, long endurance, and in-situ experimental technologies will become the core directions, but the adaptability to high-pressure environments, energy supply, and data transmission remain the main bottlenecks. Subsequently, the future development trends such as intelligentization and autonomy, long endurance and energy innovation, and the cost revolution are discussed. It is expected that this paper will play a certain guiding role in promoting the sustainable development of deep-sea exploration technology.