Rare earth element (REE) compositions and Nd isotopic signatures are important tools for tracing the formation environments and fluid sources of cold- seep carbonates. This study investigates the elemental and Nd isotopic compositions of tubular and shell- bearing cold- seep carbonates collected from two sites within the Haima cold seep in the Qiongdongnan Basin, northern South China Sea. The Sr/Ca ratios of tubular and shell- bearing carbonates range from 0.01 to 0.02 and 0.01 to 0.03, respectively, while their Mg/Ca ratios are 0.03 to 0.09 and 0.01 to 0.10, respectively. These ratios suggest that the carbonate minerals in shell- bearing carbonates are primarily aragonite, while those in tubular carbonates are predominantly high- Mg calcite. This difference indicates that shell- bearing carbonates formed under conditions of relatively high methane leakage flux and precipitation rates. Both types of cold- seep carbonates have similar total REE (ΣREE) concentrations, ranging from 36.9×10-6 to 41.8×10-6 for tubular carbonates and 36.0×10-6 to 53.5×10-6 for shell- bearing carbonates. They are characterized by enrichment in light REEs (LREEs) and depletion in heavy REEs (HREEs), with LREE/HREE ratios ranging from 11.2 to 11.6 and 10.0 to 11.4, respectively. Additionally, both types lack significant Eu anomalies (δEu=1. 03~1. 05 and 1. 00~1. 03, respectively) and Ce anomalies (δCe=0. 97~0. 98 and 0. 92~1. 01, respectively), suggesting formation in anoxic environments. Both tubular and shell- bearing cold- seep carbonates exhibit relatively low 143Nd/144Nd ratios, ranging from 0. 512066 to 0. 512096 and 0. 512059 to 0. 512087, respectively. The calculated εNd values range from 10. 8 to 10.6 for tubular carbonates and 11. 3 to10. 7 for shell- bearing carbonates. A notable negative correlation between εNd and 1/Nd suggests that the Nd in the fluids responsible for forming these carbonates is likely derived from mixed sources, with the majority of Nd predominantly originating from 143Nd- enriched water, which was released from the seawater- sediment interaction.