A gallium nitride (GaN) thin film with nanoscaled porous array structure was fabricated using nanoimprint lithography (NIL) method in this study. This obtained nanoarray was conducted using step-by-step pattern transformation strategy combined with top-down lithography on a multi-layer materials consisting of conventional PMMA, silica dioxide (SiO2), and GaN template from top to bottom. During the synthetic processes, reactive ion etcher (RIE) and induced coupled plasma (ICP) techniques were introduced in order to confine the etching speed on different mediates for optimizing the quality of patterns. After the NIL processes, GaN was grown by hydride vapor phase epitaxy (HVPE). Using the proposed technique with optimized experimental parameters, strategies fabricating the nanoscaled array patterns on GaN with expected structures were successfully developed. Results of photoluminescence (PL) and x-ray diffraction (XRD) clearly exhibited that our experimentally obtained samples with improved quality and reduced defect density (8 x107 cm-2), which is about a half of that fabricated by conventional GaN template.