A limited-ared fine-mesh 6-level model is used in this paper to simulate the explosively developing process of a East Asian coastal cyclone in March,1979.A control and four coritrastive 24h numerical experiments have been done to investigate the influence of different physical factors on the explosive development of the cyclone.The results show that baroclinic instability is the major mechanism for growth of the cyclone and condensative latent heat also plays an important role in its enhancing development.The surface friction makes the cyclone weakened and surface fluxes of sensible and latent hea.t have a slight impact on the development of the cyclone.