For prevention of tsunami disasters, a tsunami numerical simulation system for Sanriku Coast in Japan is developed.
　The system developed here can gives a result including the effects of tsunami nonlinear behavior, flow over sea walls and run-ups on land. And the system can be
applied not only to tsunamis generated in sea near Sanriku Coast but also to trans-oceanic tsunamis. Numerical grid in deep sea region of the system is set as 5,400 m, and is made small in shallow sea regions down to 50 m which could express the sea and land topography accurately.
　In order to investigate an accuracy of numerical simulation of tsunami, numerical computations are carried out for Meiji Great Sanriku Tsunami, the Shouwa Great
Sanriku Tsunami, the Tokachi-oki Earthquake Tsunami and the Chilean Earthquaku Tsunami for Ofunato, Kamaishi, Kuzi and Hachinohe port.