Beryllium (Be) is widely used in advanced science, technology, and emerging strategic fields, making it a vital strategic resource for our country. Exploring potential beryllium resource areas offers a promising solution to China' s beryllium resource shortage. The Tengchong block, characterized by complex geological processes, is an important part of the East Tethys tectonic domain. Extensive magmatic activities spanning the Early Cretaceous to the Cenozoic have resulted inthe formation of numerous tin (tungsten)- rare metal deposits in this block. Geological survey and evaluation suggest the potential for beryllium, rubidium, niobium, and tantalum rare- metal deposits in this area. The Na' e beryllium deposit, a typical granitic pegmatite- type deposit, is discovered in the Tengchong block. The rare- metal mineralized granitic pegmatite intruded into wall rocks comprisedof Early Cretaceous monzogranite. This study investigates the zircon U- Pb chronology of the granitic pegmatite, monzogranite (wall rocks), and fluid inclusions in beryl and quartz from the granitic pegmatite to discuss the ore- forming timing and physico- chemical conditions of the Na' e beryllium deposit. LA- ICP- MS zircon U- Pb dating yielded ages of 44. 3~46. 9 Ma for the beryl- bearing granitic pegmatite, whereas the monzogranite yielded an age of 122. 9 Ma. This indicates that the Na' e beryllium deposit formed during the Eocene, whereas the monzogranite (wall rock) formed in the Early Cretaceous. Consequently, we suggest that there is no genetic relationship between the granitic pegmatite and the monzogranite. Combined with the magmatic activities and tectonic evolution of the Tengchong block, we suggest that the Na' e beryllium deposit may be the result of crustal melting in a post- collisional setting caused by the convergence of the Indian and Eurasian plates. It represents a typical LCT pegmatite beryllium deposit formed during a post- orogenic stage. Beryl and quartz from the Na' e beryllium deposit contain vapor- liquid two- phase (NaCl- H2O) inclusions, with a few pure liquid- phase water and CO2 inclusions. The ore- forming fluids are characterized by medium- low temperature (172~299. 4℃), low salinity (0. 70%~3. 87% NaCleq), and low density (0. 723~0. 913 g/cm3). According to pressure and depth estimations, the Na' e beryllium deposit formed in a low- pressure, shallow environment. The concentration centers of lithium and beryllium in geochemical anomaly maps coincides patially with the locations of tin mineralization and pegmatite belts, suggesting a close relationship between rare- metal mineralization, tin mineralization, and pegmatite belts in the Tengchong block. Furthermore, the discovery of niobium, tantalum, rubidium, and lithium mineralization in this district supports the potential for widespread rare- metal mineralization in the Tengchong block. This study provides important scientific evidence for understanding the genesis and geological background of the Na' e beryllium deposit, as well as provides valuable guidance for the exploration and development of rare- metal minerals in the Tengchong district.