Abstract: With the rapid development of military optical instruments, IR optical materials have been widely used in IR optical elements and semiconductor industry, especially single-crystal silicon. To meet the precision instruments requirement for the optical system, the surface figure of the optical components has been increasingly demanded. Aiming at the processing technology requirement of high-precision silicon lens in the IR tracking system, taking a Ф26mm silicon lens as an example, by repeatedly grinding, repair/polishing, testing analysis, continuous optimization of the process parameters and designing a special fixture, this paper solved the problem of the silicon surface smoothness and the difficult control of the center deviation, and achieved mass production. After testing, the precision of the single-crystal silicon aspheric surface figure got 0.2m, the surface smoothness achieved above the grade Ⅲ and the center deviation was less than 1m. All the parameters met the requirements of the infrared tracking system.