Gallium nitride (GaN) has excellent properties such as high breakdown field strength, high saturation electron drift rate, strong radiation resistance and good chemical stability. It is an ideal substrate material for the fabrication of wide spectrum, high power, high efficiency photoelectron, power electronics and microelectronics. In addition to vapor phase method (including HVPE (hydride vapor phase epitaxy), MOCVD (metalorganic chemical vapor deposition), MBE (molecular beam epitaxy)) of GaN single crystal growth, liquid phase method (including ammonothermal method and flux method) has made great progress in recent years. In this paper, the growth principle, equipment characteristics and growth habit of ammonothermal method and flux method are introduced. The research process of two liquid phase growth methods are reviewed. The development trend and main challenges of liquid phase growth of GaN single crystal are prospected.