Compared with the traditional blanking technology such as punching and linear cutting, the laser cutting technology has many advantages. For example, it has large freedom and high working efficiency. It will not cause such problems that will affect the quality of iron core as injuries of insulation, extrusion of edge, and so on. But during the laser cutting process, the generation of dross and the rough cutting edge limit its application. A new laser cutting technology is proposed which uses an additional nozzle under the workpiece to form lateral gas flow and control the flowing direction of the slag gas. The experiments prove that glossy and dross-free kerfs are obtained by controlling the technical parameters reasonably. The gas flow under the workpiece is simulated by finite element method (FEM). The variety of pneumatic fields when the additional nozzle is in different angle and flow velocity is analyzed, and the nozzle angle of 20° is preferred, which provide experimental and academic basis for controlling the flowing direction of the slag gas and achieving glossy kerfs.