Lying in the western segment of Lunggar-Gongbo'gyamda arc back faulted-uplifted belt of the Lhasa terrane, the Lunggar iron deposit in Coqen County of Tibet is one of the important ore deposits in the Mesozoic skarn iron belt in the western part of Gandese. Field and indoor studies show that the Lunggar iron deposit is a skarn deposit related to coarse-grained monzogranite. In this study, LA-ICP-MS and SHRIMP zircon U-Pb dating of the metallogenic rock mass in the Lunggar iron deposit was conducted to probe into the ore-forming epoch of this deposit. The analytical result shows that the coarse-grained adamellite has an age of 115.5±2.1 Ma, which can approximately represent the ore-forming age of iron. The Lunggar iron deposit and the Nyicung iron deposit on the eastern side of the Lunggar iron deposit have rock-forming and ore-forming ages of 110~116 Ma, and the Luobule iron deposit between them have rock-forming and ore-forming ages of 111.3±1.6 Ma. These iron deposits are located in the same tectonic unit, have similar ore-forming characteristics and ore-forming as well as rock-forming ages, and constitute a EW-trending early Cretaceous skarn iron metallogenic belt which possibly extends westward and includes such skarn iron deposits as Bangbuqing, Longrenla and Chajiasi. In this belt, there are also late Cretaceous skarn copper-gold deposits such as the Ri'a copper-gold deposit whose ore-forming age is 87Ma. Therefore, this ore-forming belt should have the same or similar geological settings and tectonic-magmatic evolution processes. The iron-forming magmatic activity of the Lunggar iron deposit and even of the whole ore-forming belt might have to do with the underbow process of the plate, the copper- and gold-forming magmatic activity might have been related to the faulting and separating process of the oceanic crust, and the intrusion of the quartz diorite might have occurred between them.