The Youmapo tungsten-molybdenum deposit is a recently discovered large-sized skarn-type deposit in the Cenxi-Bobai metallogenic belt of southeast Guangxi. The orebodies occur as statiform, lentoid and veins in the contact zone between Youmapo complex granite and Devonian calcareousargillaceous siltstone. Up to now, 30 orebodies were discovered with more than 80 thousand tons of WO3 metal resource. Grades of orebodies are 0.191%～1.284% WO3, and 0.001%～0.019% Mo. Of them, the No. I orebody accounts for 84 percent of the total resources. Based on deposit geology research, six molybdenite samples were separated from the skarn tungsten molybdenum No-I orebody. Re-Os isotopic dating yielded an isochron age of 100.1±3.3 Ma (MSWD=0.71), and a model weighted average age of 100.37±0.62 Ma (MSWD=0.34). It is suggested that tungstenmolybdenum mineralization happened in the Cretaceous. The Youmapo complex pluton consists dominantly of granodiorite and complementary muscovite granite. Previous studies show that both rocks formed at 109.0±0.3 Ma and 109.7±1.1 Ma, but distinct differences occur in lithology, geochemistry and Sm-Nd isotopic compositions. This indicates that the both were not product of fractional crystallization but two different magmatic activities. More strong magmatism and fliud matallogenesis in the complementary intrusive rock are favorable in Tungstern molybdenum extraction and mineralization. In this study, Re-Os isotopic dating yielded the W-Mo mineralization age close to that of Youmapo complementary intrusive rock, but the time difference of 10 Ma to main intrusive rock further proves that W-Mo mineralization has close relationship with complementary intrusive rock. The Qin-Hang (Qinzhou-Hangzhou) metallogenic belt is an important nonferrous and precious metal metallogenic zone in South China Plate, with the Cenxi-Bobai metallogenic belt in the southwestern part. The precise isotopic dating of Re-Os, Ar-Ar and cassiterite LA-ICP-MS U-Pb in recent years suggests that the main mineralization ages in the Qin-Hang metallogenic belt show a gradually young trend from middle Jurasic to late Jurasic to Cretaceous from the northeast to the southwest.