Abstract:The Laojiezi Pb-Ag deposit and Baimaju Au (Cu) deposit, located in the middle section of the Jinshajiang-Honghe alkali-rich porphyry metallogenic belt, are typical mineralization centers which associated with Himalayan stage alkali-rich porphyry in Chuxiong basin, central Yunnan province. They are only 2 km apart in space, but they are different both in mineral species and mineralization types, and the metallic mineral assemblages are also significantly different. The deep structure of the two mineralization centers which in the same space and different types of mineralization is unclear, and the origin connection is also unknown, which restricts the theoretical knowledge and deep exploration of the polymetallic deposits in the Yao"an alkali-rich porphyry area. In this paper, fabric and geochemical characteristics of ore-bearing syenite porphyry and the rock association in the two deposits were compared, and the spatial distribution of mineralization elements in the deposits was summarized. The results show that: (1) the Laojiezi syenite porphyry is characterized by porphyritic texture with vein rocks developed and the phenocryst is orthoclase. While, the Baimaju syenite porphyry is characterized by porphyaceous texture and the phenocryst are orthoclase and a small amount of plagioclase. The differences in rock association and fabric features reflect that the formation depth of Baimaju syenite porphyry was deeper than that of Laojiezi syenite porphyry; (2) the geochemical characteristics of the two intrusions are consistent. They are both enrichment in large-ion lithophile elements, such as K, Rb, Ba and light rare earth elements; and depletion in high field strength elements, such as Ta, Nb, P and Ti. Major elements show that both of the syenite porphyry belonged to alkali-rich, high-K and metaluminous - peraiuminous magma series, which are associated with syenite and quartz monzonite. All this characteristics indicate that these two syenite porphyry are the products of homologous and contemporaneous magmatic evolution. However, the ΣREE and the Rb / Sr ratios of the Laojiezi syenite porphyry are higher than that of the Baimayu syenite porphyry, which indicate that the Laojiezi syenite porphyry may have experienced more intensive evolution and differentiation; and (3) the distribution of mineralization elements anomalies at three levels of the Laojiezi Pb-Ag deposit show that the Cu-Mo anomalies gradually increase to the depth.. So this deposit is characterized by metallic elements zonation from Pb-Ag to Cu-Mo-Au with depth. At the same time, from the intrusions to the exterior contact zone, the Baimaju Au (Cu) deposit shows the zoning characteristics of Au-Cu mineralization / anomaly to Pb-Ag anomaly. Based on the above studies, it is believed that the Baimaju Au (Cu) deposit, the Laojiezi Pb-Ag deposit and its deep polymetallic mineralization are closely related genesis and spatial-temporal structures. Therefore, it is suggested that there is an epithermal-porphyry Pb-Ag-Au (Cu-Mo) polymetallic mineralization system in the Laojiezi and Baimaju deposits, indicative of a deeper exploration potential for porphyry-type Cu-Mo-Au deposits. Based on this, a Pb-Ag-Au polymetallic metallogenic model was established. This research is not only significant for prospecting prediction in the deep and periphery of the deposit, but also provides reference for the study of metallogenic theory and mineral exploration in the region.