Many biomass materials, such as herbage, tobacco leaf and seaweed are chopped into small strips and usually dried by fluidized bed dryer. These Flexible ribbon particles in the fluidized bed riser may have experienced a much more complicated process, such as heat & mass transfer, mixing and drying. They are easy to hold together due to the flexibility and the non-uniformity of ribbon shape. Thus, it is important to understand the distribution of this special particle and cluster in the riser. High-speed camera method has always been used in measurement. However, it is difficult to analyze the particle flow due to the overlaps of the flexible ribbon particle in the shot image. So this paper presented a new analyzing method in order to obtain more information of this special gas-solid flow. And the radial concentration distribution of flexible filamentous particle and cluster in gas-solid flow in were experimentally analyzed. It is found that the concentration distribution of the flexible filamentous cluster was completely different from that of the conventional spherical particles.