Abstract: Some new modifications are made to the TUMMAC method which is developed dy the University of Tokyo. A new iterative scheme for the pressure of irregular star in the free surface is developed. Flaggingsare made for stream function pressure and velocity according to regular star, irregular star and air cell. The partial conservative scheme of one-dimensional Burgers equation is extended to the two-dimensional N-S equation. A solitary wave run-up on a vertical wall is simulated and analysis to the pressure distribution on the wall is made.