Microstructure and texture evolution of Hi-B steel have been extensively studied in the past decades, and the microstructures are ordinarily characterized only using a single two-dimensional plane of polished or thin foil specimen. Much information on the morphologies is lost owing to the fact that a large part of microstructure is embedded beneath the polished surface, or removed during specimen preparation. Recently, computer-aided three-dimensional morphologies have been developed which can visualize microstructure in metals. The three-dimensional visualization promotes a better understanding of the actual information of polycrystalline materials, especially when the grain morphologies and size were required in three dimensions. In this work, three-dimensional morphologies of different oriented grains which include Goss, brass, {411}<148> and {111}<112> oriented grains in Hi-B steel formed during early stage of secondary recrystallization annealing were investigated by a combination of serial sectioning, computer-aided reconstruction and visualization, and electron back-scattered diffraction technique, and then the growth behavior of Goss oriented grains before abnormal growth was discussed. The results show that Goss oriented grains mainly exhibit pagoda shape, brass oriented grains are similar to inverted taper shape, which the grain sizes reduce gradually from the surface of the sample to the internal along normal direction, and {411}<148> oriented grains also exhibit pagoda shape and inverted taper shape. However, the morphologies of {111}<112> oriented grains show irregular shape. Compared with other oriented grains, Goss oriented grains have no size advantages on three-dimensional scale, and the growth of Goss oriented grains is mainly controlled by curvature before they grow up abnormally.