Abstract: To address the issue of high failure rate of throttle position sensors in complex operating conditions of aviation piston engines, according to the principle of simplified design, a three-redundancy design scheme combining software with hardware for throttle opening signal acquisition process was proposed by establishing the mapping relationship between the output of throttle actuator and engine throttle valve opening. The software workflow was provided and the reliability formula of the redundant design scheme was theoretically derived. The calculation results based on the parameters of throttle position sensor and throttle servo products used in an engineering project show that, the reliability of the proposed throttle opening acquisition scheme operating normally for 100 hours is approximately 0.929, while the reliability when using a single sensor is approximately 0.607. Finally, a test environment was built using engine entity and test bench. By simulating the injection of typical throttle position sensor faults, throttle opening acquisition results and engine speed changes before and after the reliability design were verified. Comparative test results indicate that, according to the reliability design scheme, the engine can operate normally in the event of single fault and can operate safely in most cases of simultaneous fault. The reliability of engine operation has been greatly improved.