Underground cavity non-excavation repairing device and repairing method thereof

The invention provides an underground cavity non-excavation repairing device and a repairing method thereof.The underground cavity non-excavation repairing device comprises a bottom plate, sleeves are installed on the two sides of the top end of the bottom plate, extension rods are slidably connected to the two ends of the inner sides of the sleeves, stand columns are connected to one ends of the extension rods, first threaded rods are arranged on the inner sides of the stand columns in a sleeving mode, and first rotating discs are installed at the top ends of the first threaded rods; second threaded rods are installed on the two sides of the top end of the sleeve, second rotating discs are installed at the top ends of the second threaded rods, a heightening plate is installed at the top end of the bottom plate, a conveying mechanism is installed at the top end of the heightening plate, and a feeding pipe is installed on one side of the top end of the conveying mechanism. A feeding hopper is installed at the