The capability of the regional climate model RegCM4.5 to simulate land surface climate in dense vegetation areas is improved by changing the empirical parameter \( \alpha \) in the canopy interception coefficient in the Community Land Model, version 4.5 (CLM4.5). It is found that \( \alpha \) is a very important and sensitive parameter. After increasing the value of \( \alpha \), the simulation biases of latent and sensible heat flux in the wet season as well as the evaporation of intercepted water from the vegetation canopy (Ec) and vegetation transpiration (Et) are significantly reduced. In addition, the simulated 2 m air temperature and surface run-off in the wet season are improved obviously. However, surface soil moisture and temperature are not sensitive to the change of \( \alpha \). When regional climate simulation is conducted by RegCM4.5, the value of \( \alpha \) can be increased to 0.5 if the annual average sum of the leaf area index and the stem area index is more than 2.5, which could enhance the capability of the model, to a certain extent, to simulate the land surface climate.