Modular fiber fixed disc filter”A fiber filter disk composed of multiple square unit modules (size 0.5 meters x 1.0 meters) combined according to different sizes of the pool body, and the combined filter disk is square as a whole. The unit filter discs can be assembled and combined appropriately according to the size of the water volume. There is a backwash suction cup that runs up and down in the middle of adjacent filter discs. The suction cup is connected to the backwash pump outside the pool, and the up and down reciprocating motion of the suction cup is driven by a hydraulic push rod driving device combined with a travel switch and a lifting guide rod, achieving smooth and periodic up and down reciprocating operation. Continuous filtration of suspended solids in water to achieve national first level discharge standards.