The utility model discloses a honeycomb sandwich plate core boring tool which comprises a cutter bar and a cylindrical milling cutter, the cylindrical milling cutter is arranged on a lower bar body ofthe cutter bar, and the cutting radius of the cylindrical milling cutter is determined according to the core boring depth of a honeycomb sandwich plate. An upper positioning clamping plate and a lower positioning clamping plate are arranged at the upper position and the lower position of the cylindrical milling cutter on the cutter bar body respectively, and a honeycomb sandwich plate positioningspace is formed between the upper positioning clamping plate and the lower positioning clamping plate. The device is simple in structure and high in operability, and compared with the prior art, thewidth and the depth of the honeycomb boring core can be accurately controlled, the risk that parts are damaged carelessly to be scrapped during manual machining is avoided, and the machining quality and the machining efficiency of the honeycomb sandwich panel boring core are greatly improved.