Abstract: Piezoelectricity intelligent beam structures with interval parameters are researched in this paper. The finite element modeling of structural close loop systems for dynamic characteristic analysis is established by displacement feedback control method. The uncertainty of mass matrix and stiffness matrix are analyzed when the structural physical parameters and geometric dimensions etc are interval variables. The computation expression of structural natural frequency of close loop systems is obtained by employing Rayleigh quotient and interval algorithms. The effects of the uncertainty of structural interval parameters on structural natural frequency are inspected. In addition, the modeling and the method presented in this paper are verified through an example. The results illustrate that the interval coefficient method has important engineering value in dealing with the dynamic characteristic of close loop systems of the intelligent beam.