The invention relates to a four-body walking mechanism for an amphibious pipe-laying ship. The mechanism is used to assist in submarine pipeline laying operations. The mechanism is mainly composed of four box bodies including a box-shaped deck, a left bottom hull, a middle bottom hull and a right bottom hull, etc. Walking tracks are installed near left and right edges inside the box-shaped deck; the lower end of each walking track is connected to a towing oil cylinder; the lower ends of the towing oil cylinders on the left and the right sides are connected to the left bottom hull and the right bottom hull respectively; a steering oil cylinder is installed on the middle of the box-shaped deck; and the lower end of the steering oil cylinder is connected to the middle bottom hull. When the mechanism floats, the four bodies are locked into a whole; and the four bodies are mutually independently when the mechanism walks, and upward, downward, frontward, backward and steering motions can be realized.