When the fine sand recovery device works, the mixture of sand and water is transported to the hydrocyclone through the slurry pump. Then, the fine sand with eccentricity is conveyed to the vibrating screen. After dewatering, the fine sand is effectively separated from the water.Then, a small amount of fine sand and mud goes back to the washing tank through the return box.When the liquid surface of the washing tank rises, the fine sand is discharged from the discharge openning. The linear vibrating screen can recover material with concentration between 70% and 85%. Moreover, the fineness modulus can be adjusted by changing rotatation speed of the pump, concentration of the mortar, overflow water volume or replacing the mortar nozzle, so as to complete cleaning, dehydration, and classification.