Abstract: The Daolundaba Cu-polymetal deposit in Xi Ujimqin Qi, Inner Mongolia, occurring in the structural fissures of NE-trending fault belt, is strictly controlled by the fault structure. The deposit is of filling-metasomatic vein type, genetically belonging to meso-hydrothermal deposit. The deposit is located in the Xilinhot-Huolin Gol polymetal metallogenetic belt in the middle-south of Daxinganling Mountains, with developed structure and frequent volcanic activities. The Cu-polymetallic mineralization is in multiple stages. The orebodies are in small-medium scale, with complex shapes, stable thickness, even or uneven compositions and developed wallrock alteration.