Method for machining inner hole in part

The invention relates to the technical field of part machining, in particular to a part inner hole machining method which comprises the following steps that S1, a plate to be perforated is horizontally placed on a supporting tool; s2, the cutting machine is moved in place; s3, the cutting machine recognizes the positioning point of the plate according to a set program, the cutting machine moves a cutting head to the position to be perforated according to the set program, and the distance between the cutting head and the circle center of the hole to be perforated is smaller than the radius of the hole to be perforated; s4, the cutting machine is started to conduct cutting according to an arc striking line, the arc striking line is in an arc shape, and the tail end of the arc striking line is tangent to the circumference to be tapped; s5, cutting according to the designed circumference with the opening until the end point of the arc striking line is reached; and S6, arc suppression is conducted according to an