This paper investigates the optimized welding sequence for the fabrication of the CTBA trailing arm. The reliability of the analytical technique was verified by comparing the results of the welding residual stress analysis obtained with the commercial finite element analysis program ABAQUS for the T-shaped specimens subjected to the fillet welding and the actual test specimens. The welding deformation and the residual stress distribution were confirmed by applying the analytical technique verified through the analysis of the specimen to the real model. As a result, we identified the effect of welding deformation and residual stress on CTBA trailing arm according to the welding sequence.