Tropical cyclone (TC) intensity usually decays when it approaches a coastline. However, typhoon Meranti (1010) underwent rapid intensification after entering the Taiwan Strait and reached its peak just before landfall. Based on the best track data provided by Shanghai Typhoon Institute, China Meteorological Administration, the National Centers for Environmental Prediction Global Forecast System reanalysis grid data with 0.5°×0.5° horizontal resolution and Doppler radar observation data from "the Taiwan Central Weather Bureau" combined with a set of numerical sensitivity experiments by the Weather Research and Forecasting mesoscale numerical model, a study was performed to investigate the mechanisms of structure change and rapid intensification of Meranti (1010) after entering the Taiwan Strait. Results indicate that the topography of Taiwan offered a vital advantage for structural change and rapid intensification of Meranti. When moving northward, two mesoscale vortexes occurred over the Taiwan Strait, which resulted in a disturbance wave train of vertical vorticity alternative distribution in positive and negative values due to the shunting and leeward slope effects of Taiwan island topography. The disturbance wave trains were associated with the typhoon and strengthened the vertical motion, which was beneficial for the convection development of Meranti. Moreover, by adjusting the environmental atmospheric circulation, Taiwan topography also helped to provide a favorable environment for TC development, with stronger divergence in the upper troposphere and smaller environmental vertical wind shear. A comparison of kinetic energy budgets of TC in sensitivity experiments indicated that the disturbance wave trains and severe cumulus convection aroused by Taiwan topography enhanced the kinetic energy exchange from a subgrid scale system to a TC system to become a major kinetic energy resource for the rapid intensification of Meranti.