The purpose of this research is to develop a newly designed passive piezoelectric absorber for reducing multi-mode vibration of a cantilever beam excited by an external force. A tranditional passive piezoelectric absorber consists of a piezoelectric shunt attached to the structure, a resistance, and an inductance. The new absorber introduced here includes an additional passive loop in parallel. In the thesis, the equations of motion of the beam are derived by using Hamilton’s principle and discretized by Galerkin’s method. Numerical program is developed to simultaneously solve the equations of motion of the beam, which is coupled with circuit equations of the absorber. Different designs of the absorber circuits and different values of parameter are used to find the better results. The numerical results are confirmed by experimental results. According to the present results, the new passive absorber can achieve more vibration reduction of a structure than the tranditional passive absorber.