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The GaN growth mechanism using Li3N flux was reinvestigated by designing a new experiment that allowed us to grow GaN simultaneously under varying Ga/Li3N molar ratios. The results confirm the two-step reactions involved in the Ga–Li3N system: Li3N+Ga→Li3GaN2+Li (1) and Li3GaN2+Ga→GaN+Li (2). It is found that reaction (2) is the main cause leading to small GaN crystals in the products. Larger GaN crystals, however, can grow by a different pathway. The growing process is concerned with the formation of Li–Ga–N melt by dissolving Li3GaN2 in Li–Ga melt after reaction (1). GaN crystals up to 3 mm grow from the Li–Ga–N melt upon cooling on the GaN particles by reaction (2). Our results suggest that it is necessary to restrain reaction (2) by choosing proper Ga/Li3N molar ratios so as to obtain GaN crystals in larger size. [ABSTRACT FROM AUTHOR]