Gallium nitride (GaN) films are mainly obtained through heteroepitaxial growth in the traditional growth process, which often causes lattice mismatch and thermal mismatch, and therefore also brings serious dislocations and stress to GaN. At present, the most widespread method to reduce dislocations is epitaxial laterally overgrown (ELOG) technology. In this work, a layer of silicon dioxide (SiO2) was deposited on a sapphire-based GaN substrate and it was made into wide period mask with high mask width (window width 20 μm/mask width 280 μm) by photolithography. The 325 μm thick GaN film is epitaxially grown by hydride vapor phase epitaxy (HVPE). The sample can be released by tape. At the same time, the change trend of the crystal plane during the growth of GaN is studied through the two-dimensional Wulff construction. The wide-period mask method is of great significance for the growth of peelable, low-dislocation density free-standing GaN.