Abstract: A nonlinear dynamic model of the composite rotor blade with piezoelectric fibers was developed. The effect of the piezoelectric fibers on the frequencies and torsional damping of a composite rotor blade was investigated.The numerical results show that the change of the twist angle increases with the applied voltage increasing. When the applied voltage is equal to 1000 V，the increment of the twist angle is about 2°. Change in blade frequencies is very little with the layup of the piezoelectric fibers. When the piezoelectric fibers are arranged at 45° to the length of blade，it has a powerful effect on the damping of the torsion with the controlled voltage applied to piezoelectric fibers.