Abstract: The Haobugao lead-zinc polymetallic deposit is classified as a large-scale deposit, with the intrusive rocks closely associated with mineralization being the Ulanba rock mass, which primarily comprises monzogranite and quartz monzonite. To investigate the genesis of the rock mass and its relation to mineralization, major and trace elements (including rare earth elements) of the 2 rock types were analyzed. Results show that the SiO₂ mass fractions of monzogranite and quartz monzonite average 73.85 % and 66.94 %, respectively. Both exhibit high potassium (w(K₂O)=4.48 %, 5.72 %) and rich aluminum (w(Al₂O₃)=12.59 %, 15.10 %) characteristics. Monzogranite belongs to alkaline rocks rich in K and Ca, whereas quartz monzonite corresponds to the shoshonite series. Their rock differentiation indices (DI) range from 90.27-93.07 for monzogranite and 83.94-90.55 for quartz monzonite. The chondrite-normalized rare earth element (REE) patterns of both align with A-type granite features, enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs). Quartz monzonite has higher REE contents and exhibits a weaker negative Eu anomaly (δEu=0.70-0.96) compared to monzogranite (δEu=0.38-0.56), which has lower La, Ce, Nd, Sm, Y, Yb, and Lu contents. Monzogranite is classified as A1-type granite, while quartz monzonite is categorized as A2-type granite. Based on the regional geological context, the Ulanba rock mass is interpreted to have formed during the transition of subduction direction of the Paleo-Pacific Plate beneath the North China Plate. Regional extension in the period triggered mantle upwelling and the emplacement due to granitic magma rising. Differences in major and trace elements between the 2 granites are directly linked to the degree of mantle material mixing. Variations in alteration coefficients and metallogenic factors suggest that monzogranite is associated with Cu, Mo, Pb, W, Zn, Ag, and Sn mineralization, while quartz monzonite contributed to Cu, Bi, Ag, and Sn mineralization. Determining the main mineralization stage and related magmatic rocks provides key guidance for deep prospecting and deposit genesis studies and offers important insights into assessing the metallogenic potential of regional granitoids.