Downhole casing sand blocking device

The utility model relates to an underground casing sand blocking device which comprises a pipe body and a plurality of sand blocking assemblies, two ends of the pipe body are respectively provided with a connector, the pipe body is provided with a plurality of through holes, and the included angle between the central axis of each through hole and the inner surface of the pipe body is an acute angle. The sand blocking assembly is located in the pipe body. The sand blocking assembly comprises a mounting part and a sand blocking part, and the mounting part is arranged in the through hole; the sand blocking part comprises a plurality of steel wires, the first ends of the steel wires are all connected with the mounting part, and the second ends of the steel wires are separated from one another in a divergent shape. According to the bionics principle, a steel wire or a hairy material similar to a human vibrissa structure is implanted into the inner wall of the pipe body, when sand grains flow through the pipe body