In consideration of the effect of thermal stability of a Fabry-Perot(F-P) etalon in the satellite-borne F-P interferometer on wind measurement, this paper analyzes the thermal stability of the F-P etalon from its construction design including materials, shapes and fixed forms, then, it optimizes the design. With optimization design,the optical elements in the etalon are constructed, which shows that the two plates are all 25 mm thick, and the spacers are all 40° in angles. Then, the dimensions of mechanical structure of the etalon are calculated using flexible structure. Finally, the thermal distortions of optical elements and the etalon are discussed. It shows that the gap dimension changes in the centers of the optical elements and the etalon are 064 nm and 028 nm and the gap dimension change of the etalon is 0.2 nm when the temperature changes 0.1 ℃. Furthermore, the airglow spectral lines are ~λ/2 250 and ~λ/3 150 at 630 nm respectively, and the gap dimension changes of the etalon fall along the radius from the center to the verge. These results demonstrate that optimized structure parameters meet the requirements of measuring accuracy for thermal stability and mechanical stability at a wind velocity of 5 m/s.