Magmatic rocks in the Southern Jiangxi Province are widely distributed. The diagenetic ages of some rocks are clear, but are still in dispute for others. The U-Pb ages of the Tianxin, Lujing, Shuitou, Baie, Gaoshanjiao, Hanfang, Yangcun, Hunandong, Zhulanbu, Linyang, Dafuzu, Youshan, Huangsha,Yangbu,Wantian and other granites were obtained by using Laser Ablation-Multicollector Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICPMS). All the research results indicate that granites in the Southern Jiangxi Province experienced a long term evolution and many of them were formed in multiple stages. Although Caledonian rocks were ignored previously since they had no relationship with W deposits, they can be primary rocks for ion-adsorption type rare earth element deposits.