The invention relates to the technical field of medical instruments, and discloses a rod cutting instrument used in a spinal surgical incision, the rod cutting instrument comprises a seat body, a pushing mechanism, a fixed forceps knife, a movable forceps knife, a linkage mechanism and a driving mechanism, the seat body is in a 7-shaped bent shape, one end of the seat body is provided with a handle, the other end of the seat body is provided with a forceps arm, the fixed forceps knife and the movable forceps knife are arranged at the end of the forceps arm, and the linkage mechanism is connected with the linkage mechanism. A sliding groove is formed in the clamp arm, the pushing mechanism is located in the sliding groove, and the pushing mechanism is connected with the movable clamp knife; a linkage cavity is formed in the seat body, a driving groove is formed in the lower side of the driving cavity in a communicating mode, a guide sliding hole is formed in the upper side of the linkage cavity in a communicating mode, the linkage mechanism is located in the linkage cavity, the driving mechanism is located in the driving groove, and the linkage mechanism is connected between the driving mechanism and the pushing mechanism; the problems that in the scoliosis deformity correction operation process, due to limitation of a cutting tool, a fixing rod needs to be taken down for cutting, time and labor are wasted in the cutting process, and operation risks exist are solved.