A new method for fabricating crack is introduced by pressing the wedge on bar. The path of the crack propagation is not regular when the ratio of length and diameter is less than 1.8 on the symmetrical support. The load of the wedge for pressing the notch is given in this paper. The 2-D finite element is applied to simulate the crack propagation by the maximum normal stress theory. The experimental results show that the quality of the fracture section will vary with the span on the three-point bending. In order to control the crack propagation along the desired section regularly, the asymmetrical three-point bending is proposed. The simulation results show that when the difference of the two spans is between 11 and 22 in asymmetrical three-point bending under the parameters condition, the good quality of the section will be obtained, and the experimental results also strong support the conclusion.