Abstract: The stress concentration was the key factor responsible for the microcrack occurrence.As a further means of studying the reason why the interface delaminations occurred in the QFP structure,in this paper,the finite element program ABAQUS6.9 together with the analytical solutions of singular stress fields was used to calculate the stresses near the interface edges in the bonded bimaterials structure with the material's attributes and the structure's dimension being considered,and then the factors which affect the stress intensity factor can be found.Simulation results and analysis show that the materials' thermal expansion coefficients,elastic constants and Poisson ratio would change the stresses intensity factor's value at the interface edges.Some adjustments can be made to improve the stress state of the interface edges.Based on the determination of the K_Ⅰ,K_Ⅱ and λ,the potential interface delamination will be predicted.