The structure of a limestone kiln consists of an external metal plate,internal firebricks and middle filled loess.The foundation of a limestone kiln is built by reinforced concrete with low bar ratio and internal mortar pieces masonry with a square large volume composite structure with gray channel space.It is difficult to drill blast holes with a conventional  38 manual rock drill because of its metal outer wall.The safety of gas cut also cannot be guaranteed.Meanwhile,the internal lining of the foundation is of poor quality,with large porosity and isolated gravel distribution.Therefore,a directional blasting technology scheme is adopted to blow up a gap on the foundation of the limestone kiln and make it unstable and collapse under the action of gravity.In order to improve the construction efficiency and safety,and make the explosive energy evenly distributed in the structure,a large hole drilling rig is used to drill  90 holes on three sides(front,left and right sides) of the designed gap by reasonable design of blasting parameters.The blast holes are charged with  32 emulsion explosive bundles and tightly stemmed.The successful blasting demolition of the limestone kiln proves that it can achieve a good blasting effect,ensure the safety of blasting,and improve construction efficiency.