After the impoundment of the Three Gorges Reservoir,scouring often exists in Jingjiang River channel,in which the promoting siltation effect needs to be improved. A new type of controllable net cage structure which is ormed by meshes with equal interval is proposed.By flume experiment,the decelerating and promoting siltation effect has been analysed in different velocity,water depth and positions.The structure can improve water flow conditions in engineering areas,lower the low rate in the large spce,and achieve the purpse of siltation promoting.