The invention relates to a movable sand suction and discharge device, and belongs to the field of operation and management of hydraulic engineering. The movable sand suction and discharge device comprises a sand suction head part, a hanging steel cable, a sand conveying hose, traction steel wire ropes, floating balls and an outlet valve, wherein the sand suction head part and the sand conveying hose are arranged on a silt bed surface; an inlet end of the sand suction head part is positioned in a clean water zone; an upstream end of the sand conveying hose is connected with an outlet end of the sand suction head part; a downstream end of the sand conveying hose is connected with the outlet valve, used for controlling sand discharge flow, at the bottom of a dam; the sand suction head part is hung on a working ship on the water surface through the hanging steel cable; the sand conveying hose is connected with the floating balls on the water surface through the traction steel wire ropes; the sand suction head part sucks clean water from the inlet end, and high-speed waterflow is formed; the high-speed waterflow washes the silt bed surface, and a high-silt water body is formed inside the sand suction head part; and the high-silt water body enters the sand conveying hose from the sand suction head part and is discharged from the outlet valve under the action of water head difference between the water surface of a reservoir or a channel and the outlet valve. According to the device, energy consumption is low, the device can sectionally move on the silt bed surface, the operation is flexible, and the cost is reduced.