The sources of granite- type uranium deposit in China have been widely mentioned in previous studies. It is generally accepted by most of the researchers that the uranium sources came from the U- bearing minerals in granite. However, the course of uranium evolution during the hydrothermal alteration of granite has not been paid much attention. The Lujing uranium ore field located in the middle part of the Zhuguangshan complex granite is one of the most important granite type uranium ore field in South China. This ore field is dominated by the uranium mineralization related cataclastic alteration. The Xiaoshan uranium deposit, a newly discovered deposit,is located in the central section of the Lujing ore field. In this study, the mineralogy of hydrothermal zones from drill hole ZK- 1 in the Xiaoshan deposit has been carried out. The uraninite, uranite- thorium, monazite, xenotime, zircon, apatite and rutile have been found in the altered zones. The uraninite and coffinite- thorite host the highest uranium contents and uranium in these minerals is easily released during later alteration by oxidizing fluids. The monazite and xenotime have a moderate quantity of uranium that can potentially be liberated when they are altered to synchysite and apatite, respectively. Zircon shows stable crystal structure and does not release uranium during hydrothermal alteration. Apatite and rutile are not uranium- source minerals due to the negligible uranium content in these two minerals. Summarizing, uraninite and coffinite- thorite are the main uranium- source minerals for the Xiaoshan deposit, while Monazite and xenotime are secondary uranium- source minerals.