The invention discloses a biological pelletizing, filtering and separating device and relates to the field of biomass particle filtration and separation. The biological pelletizing, filtering and separating device comprises pelletizing equipment, a fixed box and a filter assembly. A first connecting part is located in the fixed box, a semi-gear is rotatably arranged in the fixed box, a track is transversely arranged on the first connecting part, and the semi-gear is engaged to the rack; a first elastic part is connected to the fixed box and the first connecting part; a second collecting box isarranged on a second connecting part; the filter assembly comprises a fixed frame, a screen, a discharging pipe and a connecting block; a third connecting part is arranged at the bottom of the secondconnecting plate, a first limiting part is slidably arranged in the connecting box and is connected to the third connecting part; a second elastic part is connected to the first limiting part and theconnecting box; a first electromagnet is arranged in the connecting box, and a first iron block is correspondingly arranged on the first limiting part; and a knocking assembly is arranged on the third connecting plate. The device integrates pelletizing, filtering and separating operations, so that the efficiency is improved, the manpower is saved, and the device is simple to operate, extremely high in filtering and separating efficiency and good in filtering and separating effect.