Wire arc additive manufacture (WAAM) is a new technique to fabricate large-scale complex aluminum alloy components. However, the performance of the parts is critically influenced by residual stresses and deformation. A sequentially thermal-mechanical coupled model of residual stress and deformation for aluminum alloy WAAM parts was established based on commercial FE software ABAQUS. The temperature field was calculated by the moving heat source (MHS) method. The temperature function was obtained accord-ing to the distribution of the peak temperature. Furthermore, the MHS method and segmented temperature function (STF) method were used to calculate the residual stress and deformation. The results show that the STF method satisfies both the efficiency and accuracy require-ments. 1-segment, 3-segment, and 5-segment STF methods can shorten the time for mechanical analysis by 91％, 79％, 63％, respectively. The error of the residual stress and deformation are all less than 20％. STF method provides an effective way to predict the residual stress and deformation of large-scale WAAM parts.