The relationship between oxide thickness and grain orientations was investigated using Zircaloy-4 coarse-grained specimens corroded at 500 ℃/10.3 MPa in superheated steam. The results indicate that the growth of the oxide films formed on Zircaloy-4 specimens shows remarkably anisotropic characteristics. The growth rate of the oxide films formed on the grain surfaces with the orientation between prismatic plane of (10-10) and (11-20) was fastest, and the nodular corrosion spots were formed earlier after 3 h exposure. The grain surfaces with the orientation whose poles were located at the middle of inverse pole figure started to form the nodular corrosion spots for 30 h exposure gradually. The thinnest oxide layers were detected on the grain surfaces with the orientation nearby basal plane (0001), and the nodular corrosion spots did not appeared after 30 h exposure. The experimental results show that the nodoular corrosion resistance of Zircaloy-4 is closely related to the grain orientations when the distribution and the size of second phase particles, and the solid solution content of Fe and Cr alloying elements in α-Zr matrix are at the same level.