Numerical simulations of the annual mean oceanic currents in the South China Sea(SCS) are carried out by use of the USA. Princeton University Ocean Model(POM). The effects of the structures of sea temperature (ST) and salinity (S) and the wind stress on the formation of the oceanic currents are discussed in this paper in some detail. Results show that the SCS oceanic currents can be driven by the horizontally non-uniform distribution of ST and S alone, however, the structure of such currents is in somewhat disorder, and the maximum speed is only 30~40 cm·s^-1. If the ST and S have no horizontal structure, the only wind stress drives the ocean to form orderly currents, and the maximum speed increases to 60~70 cm·s^-1. With both the non-uniform structures of ST and S and the wind stress, the currents formed are more similar to those driven only by the wind stress. It means that the wind stress is more important in the formation of ocean currents. The analysis of the free sea surface height also proves the above conclusions.