This study provides the application of damage model to complex cracked pipes which can be found especially in weld overlay region. From the perspective of structural integrity, enough basic and large-scale tests are required to accurately evaluate the components containing a crack-like defect. In this case, damage model using finite element (FE) method can be effectively used for the assessment of full-scale cracked pipes with minimum basic experiments data. The proposed method in this research is based on the stress-modified fracture strain damage model with stress reduction technique. In this paper, Battelle full-scale complex cracked pipe tests are simulated by the proposed damage model with reasonable procedure. FE simulation is conducted for basic experiments to determine failure criteria with calibrations. Then, crack initiation and maximum loads are predicted to characterize the fracture behavior of full-scale complex cracked pipes. Damage model is applied to both of carbon and stainless steel materials and verification with comparing to test data is conducted.