In the real-time image processing system, in order to solve real-time performance of the space low-pass filtering algorithm, an optimized method based on TMS320C6416 (C6416) was presented. The design applied the technologies like decomposing the low-pass filter, using the relativity of adjacent windows, using the fixed-point multiplication to implement floating-point division, reusing the intermediate result sufficiently and reducing the calculation and access of memory. The optimized algorithm is suitable for realizing on C6416 and solving real-timeperformance of the space low-pass filtering algorithm. The result shows that C6416 spares 0.8 ms after optimization and spares 6 ms before optimization. This research makes significant contributions to the method for optimization of program based on DSP.