Abstract: Heating by an electromagnetic field is an effective method for stopping internal crack propagation in metal die. In this paper, a theoretical analysis and experiment surveys are presented for simulating crack prevention by bridging over near crack tip under electromagnetic heating effect. The theoretical analysis and experiment surveys show that the tip of the crack may be melted and the welded joints can be formed when the crack is arrested by bridging over near crack tip under electromagnetic heating. So, the goal of crack preventing can be reached. The microstructure is analyzed around the crack tip after crack arresting. The superfine Martensite, fine-grained carbon compound and residual Austenites are found around the crack tip. The intensity, ductility and wearing capacity around crack tip are improved under the influence of the superfine structure.