Abstract:Located in the northwest of Hailar-Genhe Mesozoic volcanic basin, the Biliyagu ultra-large Pb-ZN-Ag deposit occurs in the Upper Jurassic Manketouebo Formation acidic volcanic and is controlled by the NW-trending faults, with the ore bodies being mainly of veined type. Analysis about the REE and trace element between volcanic wall rock and main ore minerals show they have similar distribution trend: be enrichment of large ion lithophile elements such as Rb and Th, but depleted high field-strength element such as Sr, Nb and Ta, which show both of them developed in Plate tectonic environment. The differences lie in two points: 1. Total REE and trace element of the ore mineral are bviously less than those of volcanic wallrock; 2. The volcanic wallrock behave clear negative Eu anomalies, while the ore mineral show positive Eu anomalies with different grade. Comprehensive analysis show that the Biliyagu Pb-Zn-Ag deposit belong to Volcanic-hypovolcanic hydrothermal type, the main metallogenic epoch was eorrelated to the volcanic activities during Upper Jurassic- Lower Cretaceous (140Ma±), this period was correspond to the late stage of regional tectonic transition in the north areas of China. After this metallogenic period, the deposit was transformed by the large scale magmatic activities at 120Ma±, which was caused by the quickly regional lithospheric thinning. Magmatism in this stage caused deep metamorphism and deep fluid activities related to crust-mantle interantion which strong transformed the ores and lead to the change of the REE and trace element in the ore minerals.