Abstract: The characteristics of seasonal variations of oceanic elements in the South China Sea(SCS) and its neighboring sea regions are simulated by using the improved Princeton University Ocean Model(POM) in this paper. The main results are in well agreement with that of the ocean investigations and other simulations. The results show that: the SCS branch of the Kuroshio Current is an important part in the north SCS from Jan. to Dec.; there always exists a large-scale anticyclonic warm vortex on the right of the Kuroshio Current in the whole year. In the model domain, the surface currents of the SCS are greatly influenced by the monsoon with an apparent seasonal variation. The improved POM has fair capacity to simulate the seasonal variation of sea temperature, the sudden increase of the SST and the expanding process of warm water regions to the north before and after the summer monsoon onset as well as the decrease of the SST accompanied with the winter monsoon onset are all well simulated. Those are the foundations of developing a coupled regional ocean-atmospheric model system.