A hull ultimate strength experiment device belongs to the technical field of experiment equipment, and comprises a water tank, a pressure sensor, a model ship, a first electromagnet, a second electromagnet, a second pin, a second hollow, a second support plate, a shear arm, first pins, a first support plate, a first hollow, a first motor, a bracket, a first cylinder, a second motor, a second cylinder, an impact plate, a connecting plate, springs, a third motor, roller stands, fourth motors, support blocks, rollers, a controller, a belt, a bearing, a support plate, bearing frames, screws and nuts. The water tank is filled with water. The first electromagnet is installed under the model ship. The model ship is located in the water tank. The first motor is mounted on the bottom of the insideof the water tank. The first support plate is mounted on the output shaft of the first motor. The first hollow is arranged on the first support plate. The two first pins are mounted on the first hollow. The first pin on the right side is connected to the piston rod of the first cylinder. The hull ultimate strength experiment device has the advantage that the height of the impact plate can be adjusted.