Organic carbon in marine sediments is an important indicator for the marine carbon cycle and marine environmental quality assessment. Sediment reference materials are key carriers for ensuring the reliability of organic carbon measurement data and achieving metrological traceability. Following the technical requirements of "Technical Specification for Replication of Environmental Reference Materials" (HJ 173-2017), and using the potassium dichromate oxidation-reduction volumetric method specified in "The Specification for Marine Monitoring - Part 5: Sediment Analysis" (GB 17378.5-2007) as the analytical method, this study carried out homogeneity and stability tests for organic carbon in two batches of raw material samples (HYCJW 01-2025 and HYCJW-02-2025) intended for the preparation of marine sediment reference materials. According to "Guidance on Evaluation of Homogeneity and Stability of Proficiency Testing Samples" (CNAS-GL003:2018), homogeneity was evaluated by one way analysis of variance (ANOVA) and stability by t-test. Certified reference materials GBW07314 and RMH-A510 were used for quality control. The results showed that the calculated F-values for homogeneity testing were 1.26 and 1.55, both below the critical value F0.05(19,20) = 2.14; the t-statistics for stability testing were 0.390 and 0.273, both below t(0.95,24) = 2.064. Under a minimum sample intake of 0.1 g, the bottle-to-bottle homogeneity and stability of organic carbon in the two batches of raw materials were satisfactory. The measured values of the certified reference materials all fell within the certified uncertainty ranges, indicating reliable analytical accuracy. In summary, the homogeneity and stability studies of the two batches demonstrate that both are adequate, thereby providing a technical and material foundation for the subsequent development of marine sediment organic carbon reference materials.