Inundation depth, velocity flow and resultant Froude number of tsunami were investigated both experimentally and numerically. The bottom roughness is a key factor to estimate the inundation flow of tsunami. Pressure profile acting on 2-D vertical walls and 3-D structures due to inundation flow of tsunamis were also discussed. Mechanism of the tsunami pressure acting on these different types of structures was explained. Due to the water damming up in front of the 2-D vertical wall, the maximum water depth is higher than that in front of the 3-D structure. The improved formula based on that by Asakura et al. (2002) was proposed to estimate the tsunami pressure on 2-D vertical wall as a function of the Froude number.