The invention relates to the technical field of machine tool machining and discloses an adjustable locating interference tool shank and an adjusting method thereof. The tool shank comprises a cone part and a cylinder part, wherein the cone part is used for being fixedly installed in a conical hole in the front end of a machine tool spindle; the rear end of the cylinder part is provided with an adjusting section which is sleeved with a first adjusting ring; the first adjusting ring can be moved axially on the adjusting section for adjustment; the first adjusting ring is used for backward jacking the front end face of the spindle; the cylinder part is provided with an outer thread which is used for threaded connection with a second adjusting ring; and the second adjusting ring can be moved axially on the cylinder part for adjustment and used for backward jacking the first adjusting ring. The tool shank is stable and reasonable in structure and low in cost, the first adjusting ring can beconveniently and quickly adjusted to make contact with and jack the front end face of the spindle, the adjustment efficiency is high, the tool shank has good adaptability to different machine tools and different clearance values, the situation that a large amount of match grinding work is carried out in a targeted mode is avoided, the labor intensity of workers is relieved, and the mounting efficiency is improved.