Large shaking table tests were executed to evaluate the earthquake response of a new type of supporting structure, multirow anchor-tensioned frame piles (MAFPs), to reinforce overburden slopes. This study investigates the slope’s internal acceleration field, the marginal spectrum’s total energy at the junction of the overburden and bedrock, and the force characteristics of the anchored and tensioned frame piles. The results show that the MAFP effectively reinforces the slope, significantly reducing the vibration variability between the bedrock and overburden. When the input seismic amplitude reaches 0.6 g, the peak ground acceleration (PGA) amplification factors are notably concentrated in the top area of the slope and behind the back pile, with the horizontal PGA amplification factors generally exceeding those in the vertical direction. The peak soil stress and strain on the supporting structure continuously increase with the input seismic amplitude, with a phased loading sequence: a slow increase (0.1–0.6 g) followed by rapid intensification (0.6–0.8 g). At 0.8 g seismic acceleration, significant sliding develops in the overburden behind the pile along the failure surface. Throughout the process, the front pile bears greater forces and deforms more than the back pile does. With respect to the seismic-resistant design of the substructure, it is necessary to enhance the prestress of the upper anchor cable and focus on the leading pile’s overburden-bedrock interface and trailing pile head.