The ignition ability and radiant efficiency. performances for pyrotechnic composition are related to the velocity distribution of the burning particles in its flame. Experimental research on the distribution of burning particles of the pyrotechnic composition composed of potassium perchlorate, magnesium powder and nitrocellulose was performed by a high-speed camera (HSC) photography and the mathematical modeling of flow field was carried out according to the related algorithm. The tracking statistics of particles and the analysis of velocity vector to the continuous images obtained by HSC were carried out through the succession image processing methods.The motion trajectory of the burning particles was calculated by a grey value weighted centroid method and the mathematical model of of burning particle motion vector was established. Results show that under the influence of taking into account the gravity, buoyancy, drag force etc. conditions, the coordinate of burning reaction particle and the particle trajectory model of velocity can be established, and the regional distribution of the burning particles velocity is obtained. The model can reflect preferably the characteristic of trajectory of flame particle and the flame structure of pyrotechnic composition.