Oceans cover more than two thirds of the earth's surface and are rich in oil and gas resources, biological resources, space resources and renewable energy resources. It makes life possible and sustains human society. However, the global ocean has not been explored to a large extent. Marine underwater equipment plays an irreplaceable role in the process of people's understanding and utilization of the ocean. It is the basis and guarantee for understanding, developing, utilizing, protecting and safeguarding the ocean rights and interests.

Because of the dangerous underwater environment and the limited diving depth of human beings,the underwater search usually accompanied by severe difficulties, long time and high risks, and divers are prone to be secondary injuried during their work.

Hydroelectric dams and other hydraulic buildings are located underwater, dams, energy dissipation facilities, tunnels, metal structures, berms, etc,and always with different degrees of structural wear, erosion, underwater siltation, leakage and other underwater engineering problems.

In recent years, China s offshore wind power construction has achieved rapid development, mainly in the coastal regions of Shandong, Jiangsu, Shanghai, Zhejiang, Fujian and Guangdong.

Marine oil spills have occurred countless times. The spilled oil not only brings great damage and loss to the natural environment and marine ecology and organisms, but also to human production and life and social and economic properties.

Marine environment monitoring can realize the monitoring of marine water quality. It is of great significance to timely discovery and early treatment of marine environmental damage.

Aquaculture in China covers an area of 8465 thousand hectares, of which 27.38% is marine aquaculture and 72.62% is freshwater aquaculture.