The invention relates to the technical field of a mechanical machining method, in particular to a method for blunting an intersected position of two internal intersected holes of piston pins by a rotary file. The method comprises the following steps of: 1. selecting the rotary file as a blunting cutter; 2. determining the edge part of the cutting edge of the rotary file during the blunting process; 3. clamping the piston pin on a clamp of a machining center, and abutting against the piston pin by a tailstock; 4. running a blunting program which is 4 sections helical interpolation simulation transversal program, and blunting the intersected position by the cutting edge on the back surface of the rotary file; 5. and circularly executing the blunting program which is also the 4 sections helical interpolation simulation transversal program, and blunting the intersected position of the two internal intersected holes of the 12 piston pins. The method for blunting the intersected positions of the two internal intersected holes of the piston pins by the rotary file has the advantages of having strong practicability, improving working efficiency and product quality, reducing labor intensity of employees, reinforcing the stability of blunting quality, bringing greater economical benefits for enterprises, and being generalized and applied easily.