Aiming at the problem of severe vibration of turboprop aircraft engine in flight， a high-power turboprop engine vibration isolation system is designed based on rubber vibration isolation principle to reduce the transmission of engine vibration to the airframe. Then， using the force transmissibility under the condition of rigid boundary support as the evaluation criterion of vibration isolation performance， the performance verification test platform of the vibration isolation system is designed， and the influence of different excitation on the vibration isolation performance of the engine vibration isolation system is studied by the experimental method. The experimental results show that the vibration isolation efficiency of the engine under the first-order excitation at 70 Hz is more than 95%. The vibration isolation efficiency of the engine under the random excitation from 15 Hz to 2 000 Hz is more than 75%. The loss factor of the system measured by the phase method is more than 2.2， which indicates that the designed vibration isolation system has excellent damping performance. The paper can provide technical support for the design and performance verification of turboprop engine vibration isolation system.