Abstract: With field survey and data processing, the structural characteristics of the Yunling epicontinental arc in Northwest Yunnan are clarified. This region is divided into 6 four-grade tectonic units, i.e. Xuelongshan Rock Group (Pt₁Xl), Deqing Blocks (Pz₁), Pantiange acidic volcanic magmatic arc (T₂), Gongnong inter-arc basin (T₂), Cuiyibi intermediate-basic volcanic magmatic arc(T_1-2), and Ludian volcanic arc-syn-collisional granite(T). The former two units belong to the basements of island arcs; while latter four, the main bodies. The rock associations and deformation-metamorphism of each unit are various obviously. The main bodies of island arcs were formed from Early Triassic to early Late Triassic, as a product of the westward subduction and collisional orogeny of Jinshajiang ocean basin. The main bodies of island arcs are covered by Upper Triassic strata in angular unconformity.