On the basis of ANSYS/LS-DYNA, the finite element model of single-path incremental forming of conical part was constructed. Adopting the method of numerical simulation and experiment, critical forming angle of uniform thickness in single-path incremental forming of conical part process was researched. By investigating the different forming angles of conical parts, the critical forming angle of uniform thickness of the used blank was obtained, and the influences of the blank thickness and the spindle feed step on the critical forming angle of uniform thickness were analyzed. Both numerical simulations and experiments show that the critical forming angle of uniform thickness increases gradually with the increasing of the blank thickness, while the spindle feed step has little influence on the critical forming angle of uniform thickness.