Intertidal zone cofferdam construction device and method

The invention relates to an intertidal zone cofferdam construction device. The intertidal zone cofferdam construction device is characterized by comprising a first floating body component and a second floating body component which are placed on the upper surface of an intertidal zone; the first floating body component and the second floating body component are arranged on the two sides of a soil taking area; a first tower is fixedly arranged above the first floating body component, a second tower is fixedly arranged above the second floating body component, and a truss is arranged between the first tower and the second tower; one end of the truss extends to the position above the intertidal zone from the side of the first tower; a horizontal sliding rail arranged in the length direction of the truss is arranged on the truss, the sliding rail is provided with a walking trolley, the walking trolley is provided with a winch unit and a drive device, and a steel wire rope of the winch unit is connected with a grab