The wave energy transfer caused by nonlinearity in the coastal region is investigated based on the physical experiment.Three bottom slopes (β=1/15,1/30,1/45) are installed in the flume and a set of random wave simulations based on JONSWAP spectra is generated to implement this experiment for the purpose of grasping the effect of topography.The evolution of energy for different frequency bands including the primary and higher harmonics is discussed based on the energy spectrum.Several empirical formulae regarding these dimensionless energy parameters as a function of local water depth are derived based on the data measured on each slope.The results indicate that the bottom slope plays a crucial role in the variation of the energy for the primary and higher harmonic waves.Therefore,the effect of bottom slope is considered in the final empirical formulae.