Cyclone shaft is a good sluiceway.The current works focus on the situation of rapid and large discharge or slow and small discharge.There is rapid and small flow in drainage pipe of a tailing reservoir.The paper studied the flow pattern of volute chamber of this flow by the hydraulic model experiment.In view of cyclone with rapid and small flow,the paper compared arc and elliptic curve volute chamber forms, and chose a more appropriate shape. It discussed the problems found in the process of experiment and resolved the main problems of flow pattern.By optimization,the flow pattern of recommended volute chamber of ellipse form is ideal and can meet the requirement of engineering design.