Abstract: In order to study the leakage law of the segment joint of underwater shield tunnel under the different leakage angles and different pressure heads, in the report, PFC2D particle flow software was used to simulate the leakage process from the arch to the spinner at different water levels, and the formation response induced by the leakage was studied. The results showed that in the initial stage of tunnel leakage, the fracture reduction of the contact force chain among the particles was around the leak, the instability leakage occurred, and the overlying soil was not disturbed. After the convergence stage, the number of the contact force chains increased, the formed contact force chains became the skeleton, the thicker contact force chain arches were formed around and above the leakage cracks, a stable state was reached, the particle stable arches were formed around the leakage cracks, and the obvious settling trough was formed on the surface of the sand soil. The shorter the distance from the settling trough to the center line of the leak was, the larger the particle settlement on the surface of the formation was, the approximate curve shape of the sedimentation trough was formed. With the increase of the pressure head, the particle settlement on the surface of the formation increased continuously, and the closer the location was to the tunnel center, the greater the increase amplitude of the particle settlement. When leakage occurred at the top of the arch, with the increase of buried depth, the particle settlement displacement 0.7D away from the center line of the leak seam first increased and then decreased to 0. At the 10mm water level, the maximum vertical displacement of the particles in spinner was about 2.78 times that at the arch top. More sand was leaking into the tunnel at spandrel, the leakage under higher pressure head was more unstable. After the leakage convergence was occurred in actual engineering, the secondary leakage should be prevented at higher water level of spandrel.