Abstract: A pot experiment was conducted to investigate the effects of different amounts of exogenous compound organic acids(COA) on the growth of rice, the absorption and transport of selenium(Se) in rice as well as soil properties under acidic soil conditions. The results showed that different amounts of COA had no significant effect on the grain yield of rice, but significantly increased the aboveground biomass of rice with the condition of equal Se application. The low and medium amounts of COA promoted the transport of Se to stems, leaves and grains, thereby significantly increasing the Se content in various parts of rice. Compared with the CK treatment, the low and medium amounts of COA significantly increased the Se accumulation in rice plants by 40.1% and 34.1%, respectively. However, the high amounts of COA significantly reduced the Se content and accumulation in the stems of rice by 23.5% and 46.7%, respectively, indicating that the application of low and medium amounts of COA could effectively enhance the absorption and transport of Se, while the high amounts of COA inhibited the transport of Se from roots to aboveground stems. In addition, the COA treatments significantly increased the available phosphorus content in the rhizosphere soil and the available Se content in the non-rhizosphere soil, and decreased the available sulfur content in both the rhizosphere and non-rhizosphere soils. Moreover, different amounts of COA treatments could effectively increase the activities of catalase (CAT) and peroxidase (POD) in roots of rice plants, especially the soil urease(UE) activity was significantly increased under the medium amount of COA treatment. Soil infrared spectroscopy data showed that the addition of low amounts of COA reduced the dissolution effect of root activities on kaolinite minerals, while the addition of high amounts of COA promoted the dissolution effect of root activities on kaolinite minerals. Principal component analysis indicated that soil UE activity and root CAT activity had significant contributions to the absorption and accumulation of Se in plants. In conclusion, the exogenous addition of low and medium amounts of COA can improve the availability of Se in soil, increase the activities of CAT and POD in rice roots, and significantly increase the Se content in various parts of rice plants and the Se accumulation in plants. This result provides new ideas and approaches for effectively enhancing the Se content in rice grains, which is of great theoretical and practical significance for meeting human Se nutritional health requirements.