The invention discloses a precoated sand recycling system which comprises an upright suspension combustion hearth and a horizontal type boiling bed, wherein the bottom of the horizontal type boiling bed is partitioned by lower partitioning plates so as to form a plurality of uniform bottom air distribution cabins; a hot air hole is formed in each bottom air distribution cabin; a fume exhaust hole for exhausting fume is formed in the horizontal type boiling bed; the fume exhaust hole in the horizontal type boiling bed is communicated with a fume exhaust pipeline through a flue; a draft fan is arranged at an end part of the fume exhaust pipeline; a dividing wall cooler is arranged below the air distribution cabins of the horizontal type boiling bed; the top end of the dividing wall cooler is connected with the horizontal type boiling bed through a sand falling tube; an air outlet is formed in the upper part of the dividing wall cooler; a sand outlet and an air inlet are formed in the bottom of the dividing wall cooler; the air outlet is connected with an air preheater through a first hot air tube; the inlet of the air preheater is communicated with the first hot air tube; the outlet of a gas conveying pipeline is communicated with hot air holes of the air distribution cabins through a second hot air tube.