Abstract: In the present paper we consider in the ulrasonic flexure vibration system not only with deflection deformation but also with torsion inertia and shearing deformation. We have given equi-section free free bar, cantilever bar and fixed-fixed bar, bending harmonic oscillator frequency equation and antinode coordinstes equation, about both free bar and cantilever bar frequency equation. Check by experimentation shows that the theortical values basically agree with the experimental results.