Debris flows are observed as a series of surges in nature and are characterized as rolling waves. A residual layer plays a vital role during the movement of surges. This paper examines debris flow surges in a flume to study the mass exchange between the surge front and the residual layer. Initial findings show that the surge head incorporates materials from the residual layer in a rolling way. The ratio of mass exchange increases linearly with mean flow velocity and mass exchange has an impact on the resistance coefficient.