ICP-MS method is used to study the Re-Os isotopes for molybdenite samples of Feimo Cu-Mo polymetallic deposit. It is revealed that the ore-forming age is (47.81±0.71) Ma on average, similar to the gold deposit mineralization time (50 Ma±) of Zhenyuan, Mojiang and Daping in Ailaoshan area. It indicates that northward subduction of Indian Plate under the Euro-Asia Plate in Himalayan resulted in the closet of Paleo-Tethys ocean, and during the collision orogeny, the deep material in upper mantle and lower crust are partly melting. Large-scale tectonic and magmatic activities occurred in Ailaoshan belt duo to the strike-slip and compression and brought about the melting of material of deep crust and the uplift of thermal flow.