Taiwan was affected by several typhoons each year that caused significant economic loss. Timely forecast of the typhoon movement is one of the most important tasks at the Central Weather Bureau in Taiwan. To improve the performance of the numerical typhoon track forecast model (TFS) is one of the key elements to advance the typhoon forecast of the Central Weather Bureau. In this paper, we will briefly report the TFS operational track forecast errors for typhoons in the last few years. More focus is on the comparison of the tracks predicted respectively by a finer resolution (grid intervals of 15km) model and by a coarser (grid intervals of 45 km) resolution model. The result of an impact study of including radiance observation in TFS will also be addressed. With the finer resolution, the rainfall predicted by TFS were studied. We well present some simulation results of the rainfall distribution over Taiwan area when typhoon Nari, which caused severe damages in northern Taiwan, invaded Taiwan in September 2001.