Abstract: A RAMS model is used to simulate numerically a process of cold front in June 1979 and to discuss effects of various kinds of land surface on the southward movement and transformation ofthe cold front. Results from a few set of anomaly experiments show that the topogtaphic factor plays an important role in the precipitation of southern China such that with the removal of dynamic effects of South China Mountain Range there are significant decreasees in cyclonic vorticity and rainfall at the lower level of southern China and southeast coast while the eastern Tibetan plateau and eastern China areas are subject to land-air exchanges and thermal conditions over the underlying surface.