The invention discloses a shank cutter bit detachable drill reamer, and relates to the technical field of cutters. The shank cutter bit detachable drill reamer comprises a shank and a cutter bit; thecutter bit is arranged at one end of the shank; the transverse center line of the cutter bit and the transverse center line of the shank are overlapped; the cutter bit is composed of a spiral cutter tooth and a tooth groove; the end of the cutter tooth is provided with a first threaded hole for mounting and fixing a blade; the cutter bit is provided with a second threaded hole along the transversecenter line; and the second threaded hole extends into the shank. The second threaded hole is formed in the cutter bit along the transverse center line of the cutter bit, the second threaded hole extends into the shank, through the second threaded hole, the drill bit can be easily fixed on the shank, when sharpening or drill bit replacing needs to be conducted, disassembling is convenient, the blade can be dismounted and replaced for use at any time through the first threaded hole in the cutter tooth, the times of reuse of the cutter tooth is increased, and the processing cost is reduced.