Abstract: Coral reefs are one of the most important types of carbonate sediment, preserving vital information about the Earth surface history. Research on coral reefs primarily focuses on paleoecological, sedimentological, and petrographic aspects of reef systems, with comparatively limited investigation of terrigenous input. Extensive reef carbonates have developed in the South China Sea (SCS) since the Miocene, exhibiting high sensitivity to the ocean environment. In this study, we conducted stable isotopes and element analysis of coral reef (NK-1) samples in the Meiji atoll of the Nansha Islands. Our results reveal that the Sr and Li contents are parallel to the mineralogical composition, δ¹³C and δ¹⁸O values exhibit co-varying trend, collectively indicating that these elements and stable isotopes are altered by the diagenetic processes. The Zr, Hf, and ∑REE+Y values exhibit poor relationships with δ¹⁸O values, indicating that they are insensitive to the diagenetic processes. Consequently, these elements can serve as reliable proxies for terrigenous input into the marine environment. Our study reveals that Zr, Hf, and ∑REE+Y contents remained relatively low during ca. 23 to 17 Ma but exhibited a marked increase after ca. 17 Ma. By comparing with existing paleoenvironmental records, we propose that the increased terrigenous input since ～17 Ma likely reflects enhanced sediment delivery from the entire SCS drainage system, rather than being dominated by discrete fluvial sources such as the Mekong, Pearl, or Red Rivers. We further suggest that aeolian contributions from the Chinese Loess Plateau played a negligible role in this sedimentary phenomenon.