Abstract: In this paper, we calculated heat and momentum budgets over the Sooth China Sea during a period from July to September 1981, analyzed the kinetic characteristics during active disturbance period, discussed heat and momentum redistribution of large scale field by the sub-grid disturbances. The result indicates that the disturbances have two contributions to large scale field. One is releasing latent heat that causes adjustment of thermal wind, it formes environmental field which is favourable for development of disturbances. This is a positive feedback process. Another contribution is that the disturbances dissipate momentum field, it makes the kinetic field be uniform, distroies environmental conditions which disturbances depend on. This is a negative feedback process. When the positive feedback process is superior, the disturbance develops. On the contrary, when the negative feedback process is superior, the disturbance disappeares.