In order to explore the impact of the mixed layer depth on the tropical cyclone (TC), some sensitivity tests have been conducted using a new coupled mesoscale oceanatmosphere model. The result shows that the initial mixed layer depth has great impacts on both the maximum intensity and the enhancement time of TC. Generally speaking, the initial mixed layer gets deeper, the maximum intensity becomes greater, and the enhancement time becomes longer. In addition, the relationship between TC and mixed layer depth is nonlinear. When the mixed layer depth is shallower, the TC intensity is more sensitive to its changes.