To investigate the mitigation of tsunami waves by coastal rigid vegetation, the interaction between a solitary wave and unsubmerged rigid vegetation on different beach slopes was studied by both laboratory experiments and numerical simulations. The laboratory experiments were conducted in a wave flume, and the effects of different incident wave heights, vegetation densities and beach slopes on the wave run-up were examined. Boussinesq equations were improved and validated by the experimental data, based on which the drag force coefficient of vegetation was obtained. The results show that the drag coefficient increases with the increase of vegetation density but decreases with the increase of beach slope. The dimensionless transmitted wave height behind the vegetation and the subsequent dimensionless run-up height on the slope decrease with both the increase of the dimensionless incident wave height and the vegetation density. When the beach slope is increased, the dimensionless transmitted wave height increases but the variation of the dimensionless run-up height is insignificant. Finally, an empirical power-law relation is obtained to predict the dimensionless wave run-up height through the dimensionless wave height, the vegetation density and the beach slope by regression analysis.