To improve the loading amplitude of friction based electro-hydraulic load simulator in compact size by using existing friction material, a loading method using a large amplitude torque loading mechanism is proposed, the working principle of the mechanism is described and a mechanism is designed and developed. The mechanism's finite element model is established then thermal-mechanical coupling simulation of the mechanism is conducted using ABAQUS software, and the feasibility of the mechanism is validated. The friction heat production characteristics and the friction heat impact on the loading mechanism are studied, and the simulation results indicate that in practical applications the mechanism needs fully heat dissipation. Using the developed loading mechanism, the original one-way friction based electro-hydraulic load simulator prototype is transformed as a large amplitude load simulator. Based on the transformed load simulator, under the control of a PID controller, the large amplitude torque loading experiments are conducted, and the experimental results indicate that the transformed load simulator can accurately track up to 70 N·m torque, the mechanism can improve the original load simulator's torque loading amplitude by 3 times as expected i.e., the effectiveness of the mechanism is validated.