Scanning Electron Microscopy with Polarization Analysis (SEMPA) was used to image the surface magnetic domain structure of the 100 ${mu}{ extrm}{m}$ thick 3% Si-Fe sheet. The thin-gauged 3% Si-Fe strips with magnetic induction ($B_{10}$) from 1.98 to 1.57 Tesla were prepared via conventional metallurgical processes including melting, hot-and cold-rolling, intermediate annealing and final annealing. Using SEMPA, it was observed that the $B_{10}$ (1.98 T) Tesla sample was almost composed of 180$^{circ}$ stripe domains which are parallel to rolling direction. On the other hand the 3% Si-Fe sheet with $B_{10}$ (1.57 T) Tesla was composed of large 180$^{circ}$stripe domains that are slanted about 30$^{circ}$to the rolling direction and complex magnetic domain structures like tree and zigzag pattern. The 180$^{circ}$stripe domains, which covered a major part of the sample, had (110)<001> Goss texture parallel to the rolling direction. The domain walls between 180$^{circ}$stripe domains were the conventional Bloch type walls. On the other hand, the 90$^{circ}$domains, which covered minor part on edge of the sample, were observed in (200) grains. The domain walls between 90$^{circ}$domains were the Neel type walls. In high magnification, the elliptical singularity at the Neel walls was clearly observed.