Abstract: The Sn-W polymetallic ore-concentrated area in SE Yunnan is located at the junction of the Cathaysian Massif, Yangtze Massif, and Indo-China Massif, where there are a series of Sn, W, Cu, Ag, Pb, Zn polymetallic deposits closely related to the Late Cretaceous magmatism.The Singular Value Decomposition(SVD) was applied to extract aero-magnetic anomaly components reflecting the deep geological structures and geological bodies associated with the Sn-W polymetallic deposits and mineralized granitic intrusives from the aero-magnetic data of the SE Yunnan district at a scale of 1:200 000.The results show that there are two metamorphic basements, one with strong magnetism(Dahongshan Group, Ailaoshan Group and Yaoshan Group), and the other with weak magnetism(Mengdong Group); granitoids closely related to W-Sn polymetallic mineralization in the study area shows a ring positive magnetic anomaly around a negative magnetic anomaly, which may reflect a contact skarnization zone around a granitic intrusion; and the ring positive magnetic anomalies around negative magnetic anomaly are the best targets for further exploration of Sn-W polymetallic deposits.