The concept of underwater soft robots originated from the imitation of marine biological motion mechanisms. In nature, the octopus achieves flexible bending and grasping of its tentacles through the coordinated contraction of muscle fibers. Its “muscular hydrostat” structure (shape deformation under constant volume) provides natural inspiration for flexible mechanical design. In the 1960s, the Massachusetts Institute of Technology (MIT) first attempted to use steel cables to control the opening and closing of mechanical fingers, validating the feasibility of flexible actuation. However, limited by material technology, it could only achieve single-degree-of-freedom motion.