The noise in the cabin of electric propeller aircraft seriously affects the comfort of pilots and passengers, so it is very necessary to study the noise characteristics in the cabin.SIn this paper, a certain type of electric propeller aircraft is taken as the research object.SLarge eddy simulation is used to calculate the aerodynamic noise generated by propeller rotation and it is taken as the boundary condition of the noise in the cabin.SFEM and BEM coupling theory are used to obtain the acoustic-vibration coupling sound field distribution in the cabin under the closed acoustic cavity, and the experimental field points and numerical field points are compared and verified.The results show that with the increase of propeller speed, the SPL at the head and tail of the aircraft is higher, and the test results of the total SPL in the cabin are in good agreement with the numerical results, and the maximum error of the SPL at the human ear is 3.6% in the cruising condition.SA quadratic model between the total sound pressure level (weight A) at the human ear and various test factors (material, thickness and area) was established by using response surface method to optimize the noise inside the aircraft with weight A as the target value.SThe results show that the total sound pressure level (weight A) at the human ear decreases by 12dB.SIt is proved that the calculation method of cabin noise of electric propeller aircraft is accurate and a simple and effective method is provided for cabin noise optimization.S3.6%.SA quadratic model between the total sound pressure level (weight A) at the human ear and various test factors (material, thickness and area) was established by using response surface method to optimize the noise inside the aircraft with weight A as the target value.SThe results show that the total sound pressure level (weight A) at the human ear decreases by 12dB.SIt is proved that the calculation method of cabin noise of electric propeller aircraft is accurate and a simple and effective method is provided for cabin noise optimization.S