Abstract: With dSPACE system and developed piezoelectric ceramic actuators, an adaptive truss shaped as a triangular prism was constructed as a testbed in this work. The first order natural frequency of the truss is as low as 5Hz. With the feedback signals from accelerometers on different locations of the structure, and using linear quadratic Gaussian controller based on finite element method model and parameter modification through test, the experiments and simulations of vibration control were conducted. The results show that compared to the situation without control, the vibrating amplitude of the controlled adaptive truss under an exciting with fixed frequency can be damped more than 90%, and the sustained time of vibration after disturbance can be decreased over 80% with the proposed optimal control method. The configuration of testbed is verified to be reasonable, and also the property of actuators and control modeling are valid. In simulation and experiment, the vibrating amplitudes are decreased to same value, and the difference of amplitudes decreasing processes are illuminated by the contrast of exciting processes.