The invention provides a threaded hole repairing drill bit assembly and a threaded hole repairing method. The threaded hole repairing drill bit assembly comprises a first rod-shaped body, a second rod-shaped body and a third rod-shaped body which are sequentially used in a threaded hole repairing process. The first end of the first rod-shaped body, the first end of the second rod-shaped body and the first end of the third rod-shaped body are provided with connecting portions which are connected with a spanner, the second end of the first rod-shaped body, the second end of the second rod-shapedbody and the second end of the third rod-shaped body are provided with spiral cutting knives, and the diameter of the first rod-shaped body, the diameter of the second rod-shaped body and the diameter of the third rod-shaped body are matched with the inner diameter of a threaded hole. The end portion of the cutting knife of the first rod-shaped body and the end portion of the cutting knife of thesecond rod-shaped body are provided with guide parts used for being clamped into the threaded hole respectively, and the diameter of the guide parts is matched with the tooth top circle of the threaded hole. The threaded hole repairing drill bit assembly can be used for safely and rapidly repairing the threaded hole of which threads are damaged or the threaded hole which does not meet the requirement of a measurement standard.