Based on homogenization temperature and duration of homogenization process obtained from Johannes (DH=r2/4t) and Eyring equations (DN=KB·T /η·λ), the authors calculated the viscosity of a melt inclusion at homogenization. The water content of the inclusion melt was estimated from the experimental diagram LnDH-1/T for granitic melt with different water contents. The study on mineral inclusions from Luanjiahe granite in Jiaodong gold zone indicates that the melt inclusion has a homogenization temperature of 970℃, viscosity of 3.8×106 Pa·s and water content of 2.5%, whereas the fluid_melt inclusion has a homogenization temperature of 855℃, viscosity of 617.7 Pa·s and water content of 5.8%, suggesting that during the crystallization of granitic magma water content increased while viscosity decreased continuously, and at the late stage of crystallization the fluid was close to the saturation state.