When growing the c-axis Fe doped LiNbO3 single-crystal fibers by LHPG, a cross-sectional deviation from roundness and the occurrence of bulging surface have been found occasionally. We investigated the cause of these growth habits on the basis of laser heated thermal field in the molten zone. Based on our observation of ridges at the beginning of the growth. we suggest that the seed rod type plays a very important role in the origin of these abnormal growth habits. In addition, the occurrence of peripheral facet growth has been attributed to a reduction of the thermal gradient caused by big air bubbles near the growth interface. It is also shown that these kinds of morphologies would provoke ferroelectric domain structures in the c-axis Fe doped LiNbO3 single-crystal fibers.