Internal solitons are the nonlinear large amplitude waves existing in the oceanic pycnocline. In last  decade, with more and more remote sensing data, in situ observational data and the development of numerical simulation technology, a number of studies of  the characteristics, the generation dynamic mechanisms and the propagation evolution rules in the northern South China Sea (SCS), and the estimation of the load of internal solitons on oceanic engineering were achieved. Finally, the following problems about internal solitons in the SCS which deserve to be studied are discussed, i.e., ①their synchronous observations by remote sensing and in situ field measurement, ②their sources, generation mechanisms, propagation evolution and break up, ③their prediction, ④ their effects on the marine biological environment and ⑤their effects on the submarine.