Abstract: The principle of driving point anti-resonance vibrating machines was analyzed and the expressions of the upper and lower body's steady amplitude were derived. With the upper body's steady amplitude of 5 mm and the lower body's steady amplitude of 0.5 mm, parameters were chosen according to different mass ratios and anti-resonant frequency ratios. The sensitivity formulas to the exciting frequency of the upper and lower body's amplitude were derived. Effects of the mass ratio and anti-resonant frequency ratio on the sensitivities were discussed. The results show that: when the mass ratio is invariant, the larger the anti-resonant frequency ratio is, the lower the sensitivities of the upper and lower body's amplitude to the exciting frequency are; when the anti-resonant frequency ratio is constant, the smaller the mass ratio is, the lower the sensitivity of the upper body's amplitude to the exciting frequency is, while the sensitivity of the lower body's amplitude to the exciting frequency changes little.