Internal solition is the large amplitude wave existing in the pycnocline induced by internal tide in the condition of special bottom topography. During the propagation process of internal solition,the induced disturbance can bring about strong convergence of sea surface water and sudden strong current(wave-induced current),which can cause severe threat to the ocean engineering, oil drilling platform and sea bottom oil pipeline.The dynamic state of the international study on oceanic internal soliton is introduced,the internal solition phenomena existing in the northern South China Sea(SCS) is described,some problems about internal solition study now in SCS are discussed,and the study thought is put forward.