In this study, both an atmospheric model [Weather Research and Forecasting (WRF) model] and an atmosphere (WRF)–ocean (Princeton Ocean Model; POM) coupled model are used to simulate the tropical cyclone (TC) Kaemi (2006). By comparing the simulation results of the models, effects of oceanic elements, especially the TC-induced sea surface temperature (SST) cooling, on the simulated TC size and destructiveness are identified and analyzed. The results show that there are no notable differences in the simulated TC track and its intensity between the uncoupled and coupled experiments; however, there are large differences in the TC size (i.e., the radius of gale-force wind) between the two experiments, and it is the TC-induced SST cooling that decreases the TC size. The SST cooling con-tributes to the decrease of air–sea moisture difference (ASMD) outside the TC eyewall, which subsequently leads to the decreases in surface enthalpy flux (SEF), radial sea-level pressure gradient, absolute vorticity advection, and wind speed outside the TC eyewall. As a result, the TC size and size-dependent TC destructive potential all decrease re-markably.