Abstract: The invention provides a high-water pressure trapdoor model test device and a use method thereof. The high-water pressure trapdoor model test device includes a PIV analysis unit, a liquid material, a solid material, pore water pressure gauges, first soil pressure sensors, second soil pressure sensors, third soil pressure sensors, a test box and a pressurizing unit. A box body of the test box is provided with an opening sealed by a base plate, a hole is formed in the base plate, a trapdoor is arranged at the hole, the third soil pressure sensors are arranged in the trapdoor, the first soil pressure sensors are arranged in the base plate, the solid material is placed on the base plate, the second soil pressure sensors and the pore water pressure gauges are arranged in the solid material, and the liquid material is placed on the solid material.