In this paper, a mathematical model of the coupled resonance between the up-and-down vibration and torsional swing of the Wilberforce pendulum is established, and its related influencing factors are analyzed. By building an experimental system, the motion mode of the Wilberforce pendulum is observed with the PASCO sensor, and the research is carried out based on the control variable method. The research results show that there is a resonant energy conversion between the up-and-down vibration of the pendulum and the torsional swing, and the rotational inertia of the pendulum will affect the motion state of the pendulum, and it is concluded that the coupling of the two motions leads to the “beat” phenomenon.