Lithium niobate single-crystal rods, with a diameter from 0.4 to 1.7 mm, were grown along the c-[0 0 0 1] and a-axis [2 1̄ 1̄ 0], both upward and downward, with a pulling speed from 0.5 to 10 mm/min using a laser-heated pedestal growth (LHPG) process. The axial surface temperature distribution during growth was measured. The maximum surface temperature gradient at the axial direction varied slightly with the rod diameter and was nearly invariant with the pulling speed. Crystals without cracks can be grown if the surface temperature gradients are less than the maximum acceptable axial gradient, which is roughly proportional to the diameter D-3/2. During growth, c-axis crystals crack easier than a-axis crystals. Installation of a post heating system facilitates the growth of crystals with larger diameters. The better transparency of the crystal had been grown for higher pulling speed.