The Cambrian Explosion represents a major evolutionary radiation event, marked by the rapid diversification of metazoans and the concurrent emergence of biomineralized skeletons, with diversity peaking in the Cambrian Age 3. In South China, carbonate successions preserving small shelly fossils from this interval are relatively rare, as coeval strata are dominated by clastic deposits. Thus, the Xihaoping Member and the lower Shuijingtuo Formation exposed in the Lujiaping Section in Zhenba, southeastern Shaanxi, provide a valuable carbonate record for studying early animal diversification, especially of brachiopods. High-resolution sampling combined with acid maceration and scanning electron microscopy reveals the fossil succession in this section. Based on detailed fossil occurrence data, two successive biostratigraphic assemblages are recognized in the Xihaoping Member. The lower to middle part belongs to the small shelly fossil assemblage, dominated by Turcutheca lubrica, Hyolithellus tenuis, Conotheca subcurvata, the earliest lingulate brachiopod Eoobolus incipiens, Microdictyon, Zhijinites, chancelloriids, and sponge spicules. The upper assemblage corresponds to the Parabadiella huoi Zone, defined by the first appearance of trilobite Parabadiella huoi. These two assemblages indicate that the Xihaoping Member spans Cambrian Stage 2 to Stage 3 and shows pronounced diachroneity. The basal Shuijingtuo Formation is placed in the Tsunyidiscus Zone, based on the first appearance of Tsunyidiscus yanjiazhaiensis, along with co-occurring fossils such as the acrotretoid brachiopods Eohadrotreta and Palaeotreta, the lingulellotretid Lingulellotreta, the botsfordiid Botsfordia, molluscs, tommotiids, lobopodians, and bradoriids. This brachiopoddominated succession not only refines the regional biostratigraphic framework for Cambrian Age 3 but also provides a robust basis for intercontinental correlation with coeval assemblages from the Gondwanan margins and the Siberian Platform.