Abstract: The rapid and accurate detection of soil organic carbon and its components (such as particulate organic carbon and mineral-associated organic carbon) is of great significance because they are the key indicators reflecting soil quality. Compared with manual titration, the automatic titrator has a low work intensity and accurate detection, but its detection efficiency is less than 30% of that of manual titration. To solve this problem, the influence of the addition amount of four oxidants on the determination of organic carbon was explored, and the effect of pre-adding titrant in advance on the improvement of detection efficiency was studied. Finally, the optimal addition amount of oxidant was 2mL, and the amount of the pre-added titrant was one-third of the titration amount of the blank sample. An automatic titrator method for the determination of soil organic carbon was established. This method was verified by using soil samples with different levels of organic carbon and reference substances and was compared with manual titration. The results showed that there was no significant difference between the automatic titrator and the manual titration. The relative standard deviation (RSD, n=6) of the method was 2.10%−12.96%, the recovery rate of standard addition was 93.37%−98.06%, and the relative error of the reference material was 4.31%−4.79%. The titration time of a single sample was shortened from 11min to 3.5min, and the overall detection efficiency was higher than that of manual titration. The reagent consumption was only 40% of that of manual titration. The automatic titrator significantly improved the detection ability of organic carbon.