The invention discloses a graded filtering device with an anti-blocking function. The graded filtering device comprises a base body, a sliding groove, a guide column, a main flow pipe and a high-pressure nozzle, the inner surface of the base body is provided with the sliding groove, the inner surface of the sliding groove is slidably provided with a sliding block, the outer surface of the sliding block is connected with the guide column in a penetrating manner, the inner surface of the base body is fixedly provided with a limiting plate, a sieve plate is mounted on the outer surface of the sliding block in an embedded manner, a discharge plate is fixedly mounted on the outer surface of the sieve plate, a main shaft is mounted on the outer surface of the sliding block in an embedded manner, and a secondary support is fixedly mounted on the outer surface of the main shaft. According to the graded filtering device with the anti-blocking function, a scraper used for cleaning the sieve plate is arranged, the scraper and the sieve plate in the device move in the opposite direction in the using process, objects stuck or blocked by the sieve plate can be cleaned up, the scraper can perform reciprocating linear movement through a moving rod during use, so that the scraper can move along with translation of the sieve plate conveniently, and use of the sieve plate in the working process is not affected.