The utility model relates to an elasticity loose -leaf formula mechanism that cores that resets, including the valve seat, valve seat upper end can be connected with the inner tube or the outer tube of core drill, still includes lower section of loose -leaf subassembly and pipe shoe, and several loose -leaf subassembly evenly distributed is respectively fixed in the valve seat, lower section frombottom to top cartridge of pipe shoe in the valve seat, upper end that pipe shoe is lower section when creeping into to below pressure every loose -leaf in several loose -leaf subassembly on, throughthis technical scheme, adopt cylindrical screw torsion spring as loose -leaf restoring force, improved the reliability of mechanism greatly, hinge the loose -leaf through loose -leaf shaft and the cooperation of loose -leaf reaming sleeve and fix in the valve seat to effectual quality and the efficiency that has improved geotechnical engineering investigation satisfies the needs that the production technology develops betterly, has the function that does not make core appearance drop, and core recovery percent is not less than the regulation of relevant standard, original state soil property volume reaches I ~ II grade of standard.