Abstract: In this paper, using the continuous dymantic grid adapation technique,Typhoon Helen(1995) and Willie (1996) in South China Sea are modeled. It is found that the dissipations of typhoons are related to the increase of the intensity of subtropical high.The orographic effect isn't important.The actions of the high is very sensitive to intensities of the typhoons.When the high's intensity decreases, the typhoon increases and when the high's increases, the typhoon decreases. The cumulus convection latent heating is an important factor for maintance of typhoons.The intensity of high is inverse proportion to the heating. If a landing typhoon comes close to the westerlies trough,it is helpful for the maintance of typhoon.