Abstract: The Jiangdong granites are located in the Jiangdong-Xiangqiu of Mangshi, the western yunnan Tengchong block.Field investigation has found that Jiangdong intrusion consists of biotite monzo-granite. Most of the Jiangdong granites is from the original Gaoligong Group group disintegration by the author through the 1:50000 regional geological mapping.To limit the precise age of the Cenozoic magmatic mineralization in the Mangshi area,the Jiangdong granites have been analyzed using LA-ICP-MS zircon U-Pb techniques and geochemical methods.The zircon LA-ICP-MS dating indicates that the biotite monzo-granites was emplanced at 58.29±0.44Ma. The granite mass is formed in the Paleocene. Geochemical data show that the Jiangdong granites are k black to high-K cale-alkaline series,characterized by medium content of SiO2（68.66%～73.50%）, high K（K20/Na20=1.87～2.20） and peraluminous ratio( A/CNK)=0.97～1.36). The biotite monzo-granites is riched in Th、U、Rb and Ba,and depletion in Tb、Nb、Zr and Hf,belong to k black to high-K cale-alkaline peraluminous S-type granites.which are similar to calc-alkaline rocks in island arc or active continental margin. The ΣREE ranges from 158.85×10-6～304.26×10-6, REE diagram shows rightward incline and obvious negative Eu abnormity. Magma source is probably rising and emplacement of partially melt granitic magma dominated by greywacke , which is typical of crustal genesis. Magma source is probably rising and emplacement of partially melt granitic magma dominated by greywacke , which is typical of crustal genesis. The Jiangdong biotite monzo-granite was derived from partial melting ofthe Mid-Proterozoic metamorphosed basement (Gaoligong Group)。According to geochemistry and the trace element discrimination diagrams for tectonic interpretation,the the Cenozoic granitoids are considered to be of the post-collision type formed in a transitional tectonic setting from the compressional system to the tensional system. The Jiangdong granites probably formed in a post-collisional setting，which may imply that the Indian plate collided with the Gangdese-Bomi-Tengchong block before 60Ma (prior to Cenozoic). The Gangdese-Tengchong tectonic belt entered the tensional stage. The Gangdese-Tengchong block tectono-magmatic orogenesis was intimately related to the closure and subduction and collide orogenesis of the new-Tethys Sea.The determination of the Jiangdong granites’s crystallization provides new evidence for the Cenozoic tectonic evolution of the Tengchong massif．