Abstract: The present invention relates to a double-screen grinding mechanism and a double-screen grinding juicer, belonging to the technical field of household appliances. The juicer comprises a motor box, a motor, a middle cover, a grinding mechanism and an upper cover, wherein the grinding mechanism consists of a filter screen and a rotor, the filter screen being of a double-layer filter screen structure and comprising an upper filter screen and a lower filter screen, the rotor comprising an upper rough-grinding portion and a lower fine-grinding portion; the motor is mounted in the motor box; the middle cover is fixed on the motor box; the filter screen is mounted within the middle cover; the rotor is located in the filter screen; the upper cover is covered on the middle cover to shield the filter screen and the rotor; and, the rotor is connected to the motor via a rotor shaft.