Experiments were performed in a long wave channel of 163 meters in order to investigate the deformation of tsunami propagating in a continental shelf. Abilities of coastal structures in reducing the tsunami run-up were also examined. Two types of experiments were performed, namely, one is the small scale experiments (model scale is 1/200) in which deformation and run-up of tsunami without structures were mainly investigated, the other is the large scale experiments (model scale is 1/50) in which effects of coastal structures on tsunami run-up were in vestigated. 　Peregrine's model was used in order to calculate the deformation of long waves and the development of solitons at the head of the bore. The mean height of the bore was well explained by Kishi's finite amplitude long wave theory. 　Coastal structures used in the experiment were offshore breakwaters, composite breakwaters and seawalls. Abilities of such structures in reducing the tsunami run-up were investigated and compared each other. 　It must be recognized that the opening of offshore breakwaters reduce the ability to a certain extent for tsunami run-up.