Abstract: As an important indicator and accumulation space of marine oil and gas, the submarine canyon (SC) is an important subject in marine oil and gas exploration for the time being, especially its hydrodynamic system. The hydrodynamic system includes gravity flow, turbidity current, tides/internal tides and wave, bottom currents, upwelling and Dense Shelf Water Cascading, et al. They are obviously different from the systems out of the canyon. We discussed in this paper the hydrodynamic elements and their impacts on submarine erosion, sediment transport and sediment deposition as well as the unique ecosystem as a force. Major research means are also discussed. The results show that the consequences of the hydrodynamic processes mentioned above are different due to their different origin. Forces, such as gravity flow, internal tide and upwelling current, affect canyon’s topography, sediment transport and ecosystem in different manner, and the four study methods for hydrodynamic study all have their own limitations.