The Taiwan Strait is a shallow channel with complicated topographic variations that connects the South China Sea with the East China Sea. Previous hydrographic and numerical studies have suggested that a distinct feature of the flow pattern in the strait is the transfer of the vertical stratification of the incoming flow from the south into the horizontal density gradient in the middle of the northern portion of the strait. This work applies a numerical model with a free surface to examine the influence of a change in the volume transport on the density distribution in the strait. According to the model results, a reduction in the incoming flow rate will cause a weakening of the original density gradient. The release of the available potential energy associated with the original density gradient causes the current to meander. The model results are consistent with the satellite sea surface temperature images on 12 and 17 August, 1998.