The utility model relates to the technical field of
aquaculture, and discloses a drainage device for crab breeding in a rice field, which comprises a stable pressure regulating mechanism, a pressure regulating mechanism, a pressure regulating mechanism, a pressure regulating mechanism, a pressure regulating mechanism, a pressure regulating mechanism, a pressure regulating mechanism and a pressure regulating mechanism, and is characterized in that the stable pressure regulating mechanism comprises a stable box, and a first
piston cylinder and a second
piston cylinder are arranged on the upper surface of the stable box; through cooperation of a stable pressure regulating mechanism, a connecting piece, an
impurity removing mechanism and a water draining mechanism, media in a first
piston barrel, a stable box and a second piston
barrel are compressed through a
variable pressure assembly, so that the height of the connecting piece is adjusted, the height of the water draining mechanism is conveniently adjusted, water in a rice field is conveniently pumped, and the water draining efficiency is improved. The
water level in the rice field is controlled by controlling the height of the water drainage mechanism, so that the water drainage efficiency in the rice field is improved, operation is easy and convenient, convenience is improved, sundries attached to the water drainage mechanism are conveniently scraped through vertical movement of the cleaning ring, the influence on the
water flow efficiency is avoided, and the water drainage efficiency is improved.