Abstract: A study on the Stress Intensity Factors (SIFs) of off-center kinked cracks in the three-point bending beams has been conducted using the Singular Isoparametric Element Method. The microcomputer program used to calculate the SIFs of cracks is reliable and easy to run. The calculated results show that it is more reasonable to substitute kinked cracks by corresponding inclined cracks in the calculation process. Also, the fitting formulae about the SIFs of inclined cracks of β=25.5°are made through a series of calculations. Moreover, significant problems which would affect the accuracy of the results, such as selection of the size of the crack tip element and the transition element, and the demarcation of the connective elements, etc., are discussed in this paper.