Tinggong is a large porphyry Cu deposit located in the western segment of the Gangdise porphyry Cu belt in southern Tibet. It contains 1.49 Mt of Cu with an average grade of 0.362% and 0.04 Mt of Mo with an average grade of 0.018%. The deposit consists of both collisional and post-collisional stage porphyry-type Cu systems, which are genetically associated with the early Eocene coarse-and fine-grained granite and the Miocene monzogranite porphyry stock, respectively. It is the most important deposit in the Gangdise porphyry Cu belt, but geology of the deposit remains poorly constrained. In this paper, the authors conducted a detailed study of geological features of the deposit, so as to ① document the geological characteristics (e.g., alteration and mineralization) of the deposit; ② investigate intrusive sequences and magma source of main intrusions in the deposit; ③ investigate tectonic control of intrusion emplacement, alteration and mineralization; ④ track fluids evolution process; and ⑤ determine genesis of the deposit. On such a basis, the authors formulated a genetic model for the Tinggong deposit.The authors surveyed the petrography-alteration of the Tinggong copper deposit, and exactly determined the distribution of formations and magmatites. In combination with zircon U-Pb isotope dating results of other researchers, the authors built up a detailed series of magma evolution. It is shown that there existed two peaks of magmatic events, i.e., K-feldspar granite in Eocene (~50 Ma) and porphyritic monzonite granite, tonalite porphyry and diorite porphyry in Miocene (13~17 Ma).Through field and lab research, the authors have come to the conclusion that there occured two phases of mineralization events in the Tinggong deposit, i.e., copper mineralization in Eocene (~50 Ma) and Cu-Mo mineralization in Miocene (~15 Ma). Moyite formed in Eocene, which has a particular texture, i.e., it has no classical porphyritic texture but shows unique fine grain-like pegmatite texture. This suggests the existence of sudden cooling of the ore-bearing magma, which might have been caused by the sudden escape of fluids. There also exist large quantities of micro graphic texture, quartz eyes and some other textures. These special textures imply that the magma was rich in water and the fluid was once in a saturation state. Porphyritic monzonite granite was associated with Cu-Mo mineralization in Miocene.The alteration zoning of the deposit is similar to that of other porphyry deposits in Gangdise. In term of time, the alteration was potassic alteration in early period, propylitization occurred in a transitional phase, followed by phyllic alteration and argillization. In term of space, from the core to the outer part there are potassic alteration, phyllic alteration, and propylitization. The latest argillization exhibits patch or banded form, superimposed upon other alterations of earlier time. The authors described all kinds of alterations, mineral assemblages and associated veins in detail and dealt with the evolution process of the fluid as well as the source and accumulation mechanism of metals.