Controlling the development of {100} texture in non-oriented electrical steels is important for improving the magnetic properties in this class of materials. In this paper, a {100} textured Fe-3 %Si-1.7 %Mn-0.05 %C silicon steel sheet has been processed by vacuum annealing and subsequent decarburization following the heavy cold rolling of a hot-rolled slab. After vacuum annealing, the surface layer transformed into thin alpha-ferrite with columnar grains, which grew inward during the subsequent decarburization annealing at the alpha + gamma duplex temperature. It has been demonstrated that cold rolling to high strains and increasing vacuum annealing temperature are the key factors for improving the {100} texture of the surface layer in a relatively short vacuum annealing time. Moreover, the formation of the {100} texture is attributed to the retention of the {100} texture formed during cold rolling and a growth advantage in the stage of vacuum annealing. The development of a strong {100} texture in the surface layer ferrite is strongly related to the growth advantage of grains with the {100} orientation, which consume the non-{100} grains during the vacuum annealing process.