A novel gravity blender with an inner downcomer was experimentally studied in this work. The flow characteristics of solid through the downcomer with branch pipes and the influence of the number of intake openings and their axial position along the downcomer on blending efficiency were investigated. The results of tracer experiments show that better blending quality can be obtained if the intake openings along the downcomer are designated according to the equal time interval principle. More intake openings are beneficial for blending efficiency, and the solids Row rate through the branch pipes along the downcomer can be predicted by the Beverloo equation.