The invention discloses a device for removing back soil of a shield shell of a shield construction machine and an application method. The device comprises two or more rotation assemblies and a slidingassembly, the rotation assemblies and the sliding assembly are arranged on the interior and exterior of the shield shell respectively, and traction ropes wind the rotation assemblies respectively, penetrate through the shield shell separately and are connected with the two sides of the sliding assembly; when the rotation assemblies rotate to drive the traction ropes to be folded and released, thesliding assembly slides along the outer wall of the shield shell in the circumference direction. According to the device, during use, the rotation assemblies rotate to drive the traction ropes to befolded and released, the sliding assembly slides along the outer wall of the shield shell in the circumference direction, and the back soil of the outer wall of the shield shell is scraped accordingly; large-sized back soil above a shield shell body is scraped through a mechanical method, the back soil at the top of the shield shell of the shield construction machine can be effectively reduced, and normal running of the shield construction machine is guaranteed.