Abstract: In order to study the influence of geometric structure parameters of corrosion pits on the tensile mechanical properties of welded joints, a finite element model of tensile fracture of titanium alloy welded joints containing corrosion pits was established based on the Johnson-Cook fracture theory. The Dynamic Explicit algorithm was used to solve the finite element model, and the accuracy of the model was verified by comparing the simulation and experimental results. The results show that large stress concentration occurs in the corrosion pit region, which is the main reason for the reduction of the load-bearing capacity of the welded joint. The load-bearing capacity of the welded joint reaches the minimum when the long axis of the corrosion pit is at or near 90° to the loading direction. The equivalent stress and plastic strain in the corrosion pit region first increase and then decrease with the increase of the pit orientation angle β and reache the maximum value when β= 90°. In engineering design and application, we should focus on the long axis of the corrosion pit and the load direction into 90° or near 90° of the corrosion pit, strengthen the monitoring and prevention of such corrosion pits.