Abstract: The Yangcun granite mass is located northeast of Nanling and Xingguo country of the South Jiangxi area. It intrudes into metamorphosed rocks of Precambrian basement, and is adjacent to Cretaceous Sandstone and conglomerate at its west side with a fault. The forming time of this granite masses is difficult to judge correctly by its contact relations, and it was previously assigned to the Caledonian period. In this paper, we give a U-Pb age of (175.8±1.0) Ma of zircon by Laser Ablation-Multicollector Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICPMS) dating technology, thus ascertaining this granite mass as an intrusion during the period between the first and second stage of the early Yanshanian, and this period is the onset period of extensive mineralization of tungsten and multi-metals in the Nanling area. Therefore, the determination of the geochronology of the Yangcun granite masses will provide new information for prospecting in the future.