Abstract: The biological material has the characteristics of rich morphology, wide particle size distribution, short growth cycle, low mass density. It is significant to study its performance characters for development of new extinction material. In order to study the diffusion characteristic of biological extinction material, according to Rechtman diffusion theory, the diffusion model of biological material was established. The diffusion of biological material in typical natural environment was simulated, and the effects of wind speed and surface roughness on the diffusion of biological material were quantitatively discussed. The results indicate that the maximum value of concentration of biological material on reference point was continuously reduced, and the spatial position of maximum value maximum value of concentration was also changed. The higher the wind speed and the greater the surface roughness, the faster the diffusion rate of biological material was.