Abstract: The dynamic response of seabed induced by cyclic loading at the subaqueous delta of the Yellow River is simulated by hitting a load plate with hammers of different weights dropped freely at different heights. In the seabed, the vibration detectors and pore pressure gauges are buried to observe the vibration energy dissipation and pore pressure variation, and the soil strength is also measured before and after vibrations. Through the observation, some conclusions are drawn: 80% of the loading energy is absorbed above depth of 0.6 m, and the relationship between dissipation degree and depth can be expressed by the logarithmic curve; the excess pore pressure increases with the increase of the vibration energy; according to the variation of pore pressure with vibration times, the variation of pore pressure can be divided into four stages—initial stage, growing stage, stabilizing stage and attenuating stage. Finally, the variation of soil strength induced by vibration and the relationship between soil liquefaction and vibration energy are discussed, and the concept of critical liquefaction power is put forward.