Slurry backfilling system for closed reclamation of large pit type tailing pond

The utility model discloses a slurry backfilling system for closed reclamation of a large pit type tailing pond, which comprises a slurry discharging backfilling device, the slurry discharging backfilling device is formed by combining a slurry discharging pipeline (8) and a plurality of floating and sinking cylinders (7), and the plurality of floating and sinking cylinders (7) are bound at two ends of the slurry discharging pipeline (8) and stably suspend on the water surface in the pit type tailing pond; one end of the slurry discharging pipeline (8) is connected with an outlet of an external slurry conveying pipeline, the other end of the slurry discharging pipeline (8) is a blind pipe, and slurry discharging holes (11) are formed in the lower portion of the slurry discharging pipeline (8). And the mixed slurry is conveyed into a slurry discharging pipeline (8) of the slurry discharging and backfilling device and is discharged through a slurry discharging hole (11), so that soil covering is carried out on a