As an optical frequency discriminator for the Rayleigh channel of the Doppler wind lidar,the performance of F-P etalon determines the accuracy of the wind measurement and the performance of the Doppler wind lidar.The F-P etalon converts the frequency change into energy change for frequency discrimination,echo signals with different frequencies have different transmittances,and the transmittance of the etalon is affected by many factors.From the Airy curve,the influence of different factors on the transmittance of the etalon is studied,and the change rule of peak transmittance with different factors is obtained.It provides the parameter basis for the simulation,design and the measuring error of Doppler wind lidar.