Abstract: Concentrated on the mismatched welded joints contain defects located at its fusion line,the stress-strain fields distribution was analyzed by elasto-plastic finite element method with mixed mode loading.The fracture parameter crack opening displacement and its compound angles were also calculated.The simulated results show that the effects of load angles on the welded joints are more significant than that of strength matching parameters when the loading angle is small.But the effects of strength matching on welded joint are more evident than that of the loading when the loading angle exceeds 30 degree.