Numerical analysis was attempted to make clear the relationship between flow behavior in the slump flow test and rheological coefficients of high-flow concrete. Compared with experimental data, it was ascertained that numerical analysis simulates flow behavior in the slump flow test accurately, if plastic viscosity-yield value ratio, η_pl/τ_y, exceeds 1.0sec. Then the influence of plastic viscosity and yield value on reaching time in 200mm and 250mm radius, and also a method of obtaining rheologacal coefficients of high-flow concrete were demonstrated by using numerical analysis.