In view of the current situation of less research on amphibious robots in China and the low degree of robot intelligence, this study aims to design and manufacture an amphibious multi-legged intelligent robot, including the structural design reflecting its amphibious motion characteristics, bionic characteristics and the corresponding attitude and motion control system research and development. It responds to the demands of technological development in the field of underwater robots, with high scientific and technological content and strong interdisciplinary. The robot has 3 degrees of freedom for each moving limb, so it has strong mobility and high passability to deal with complex terrain. The robot is equipped with a single-chip microcomputer-based control system, and the land movement relies on the steering gear to drive the joint swing and the research of gait algorithm, reflecting the bionic characteristics; the underwater movement is based on its own vector nozzle thruster, which realizes the directional propulsion control of the underwater movement attitude, and is equipped with a magnetically coupled vector control thruster based on the "Kangda effect", which greatly improves the flexibility and maneuverability of underwater attitude adjustment. Its stable operation, breakthrough in gait research and mechanical structure design, high passability, strong amphibious movement ability, foot stress materials can identify a variety of different road conditions. The overall design can switch between autonomous cruise mode, group control mode and human-computer interaction mode. Imitating the appearance of jellyfish design can greatly improve the resistance and compression characteristics and the overall mass distribution of the fuselage. Its balanced joint design fully integrates the advantages of flexibility, stability, strong mobility and high propulsion efficiency of underwater motion. The robot has reached the advanced level in related fields in terms of structural design innovation, gait theory analysis, body waterproof technology and application of new materials. With it as a platform, it can be equipped with high-definition cameras and various high-precision sensors to perform surveying and mapping exploration, data collection, water quality detection and other special tasks in land and underwater areas. It has a wide range of application prospects and significant social value.