The frame of ROV is used to install and protect various underwater equipment. Most manufacturers use open frame structure to improve the stability of the whole machine. This structure is also convenient to add auxiliary equipment, and the water flow can pass through the body unimpeded. Some ROV manufacturers also integrate the frame with the electronic warehouse, even the integrated structure. There is no obvious distinction between the propulsion system, pressure shell, floating block and frame. If the shape design is good, it is easy to cause turbulence, increase resistance and poor stability. It is suitable for those small observation level ROVs.