Abstract: Based on the volumetric method, the determination of carbonate content in marine sediment was carried out by automatic potentiometric titrator with related software-tiamo, which can export the results automatically. This method is simple and rapid for batch measurement. The results were consistent with standards defined by the National Standard Reference of Deep-Sea Sediment. Seven independent determinations were measured for the same sample, and the standard deviation of the results was less than 0.9%. Several samples of sediment core MD06-3050 were used to measure carbonate content by automatic potentiometric titrator and ICP-OES. The results of two methods were consistent.