Based on the energy conversion system of flow induced vibration, this paper tests the combined triangular prism with the section form and stiffness as variables to evaluate the amplitude, frequency and other indicators. The combined triangular prism is selected for model test, as well as the influence of arrangement and stiffness on the combined triangular prism is studied by changing the arrangement of the prisms and system stiffness. The aim of this study is to explore the optimal condition for flow induced motion of the three triangular prisms in different arrangements, and to expand ideas for subsequent research on flow induced motion of multiple oscillators. The experimental results show that all the combined triangular prisms have good performance with different stiffness. Both the motion of Type I prism and Type III prism perform typical vortex induced vibration with the increase of flow velocity. The Type I prism has the best performance with a maximum amplitude ratio of A*=0.85 (K=1400N/m, Ur=7.5).