The Early Paleozoic basin center of the South Qinling is located in the area of Ziyang and Ankang. The sedimentary basin can be classified into two sequences atⅡ-class and five at Ⅲ-class. In black rock series existing in sequence I and sequence IV, barite and witherite occur near by the conversion interface between the transgression and the highstand systems. The basin evolution experienced five stages from initial subsidence (∈1 including some Z2) to transitional (late∈1-∈3)-stable (O₁-early O₃)-intensive (late O₃-early S₁) subsidence and atrophy period (late S₁-S₃) of the basin.