Microstructure evolution in E-form and AZ31 magnesium (Mg) alloys was studied via ex-situ mini-V-bending tests. Initially, the E-form and AZ31 Mg alloys had different crystallographic textures and average grain-size distributions. Direct observation of microstructural evolution during the ex-situ mini-V-bending tests was experimentally observed via electron back-scatter diffraction (EBSD) technique. The EBSD results revealed how twin bands (TBs) developed at different punch strokes (PSs) in the deformed grains made a significant contribution to the localized deformation zones in both Mg alloys under the mini-V-bending process. Eventually, the TBs and grain boundaries (GBs) in the localized deformation zones were responsible for crack initiation sites in the tension region. At lower PSs, compression (CTW) and double (DTW) twins were more prominent in E-form than in AZ31 under the mini-V-bending process. High-resolution cross-sectional t-EBSD analysis showed that surface relief allowed the grains residing on the free surface to be less affected by stress concentration while the sub-surface grains were more affected by stress concentration, which promoted the development of twinning. © 2018 Elsevier B.V.