Abstract: An infrared (IR) image air defense missile searching and tracking algorithm based on digital signal processor (DSP) was proposed. The algorithm was divided into two parts, the contour approximate curvature algorithm was used for missile tracking with tail-smoke; the small target tracking algorithm based on region growth was used for burning tracer tracking. The algorithm was implemented in C6416 DSP platform. Outfield experimental results indicate that the algorithm is capable of realizing the air defense missile optoelectronic tracking and guidance.