Abstract: In order to optimize the system's total performance, aiming at missile tracking system, a kind of infrared optical system with the principle of conformal optics was designed in this paper. Firstly, according to the missile's flying information, through numerical simulation computation and relative wind tunnel experiments, the outer figure of the conformal dome was gotten. By optimizing the optical path differences, the inside figure of the conformal dome was obtained. By using the Wassermann-wolf equations and the Zernike aberration analyzing method, the fixed two pieces correctors were designed for correcting the aberration induced by conformal dome. The detector used in this system was a F=2 mid-wave infrared detector made by Sofradir in France. The imaging optical system was designed in refraction/reflect structure, then by using software ZEMAX the final system was gotten. Finally, the tolerance analysis was done. The focal length of this conformal optical system was 120 mm, the cold diaphragm efficiency was 100%, the MTF(modulation transfer function) of all fields are all above 0.6. Even after the tolerance analysis, the MFT value was also above 0.4 which is good enough for manufacture. The results of imaging tests show that this kind of conformal optical system is good in imaging.