Abstract: To explore the effects of applying different concentrations of selenium-enriched organic fertilizers on the yield of coix seed and the selenium content of coix seed grains, and to provide theoretical basis and solutions for the selenium-enriched technology of coix seed. Two local coix seed varieties, GUI Nong Yi 7 and Xing Ren Xiao Bai Ke, were selected for the experiment. 14 selenium concentration treatments of 18, 54, 162, and 486 mg·kg⁻¹ were set up, along with one blank control of 0 mg·kg⁻¹. Three repeated experiments were conducted for each variety, totaling 30 plots. Through unified planting methods and field management, the yield of coix seed is measured after it matures, and samples are collected to test relevant indicators. The results showed that the yield of Guinan Yi7 after selenium treatment was higher than that of the control, and the medium and low concentration treatments（C1 and C2）showed significant yield increase in plots A1 and A2, while in plot A3, the high concentration treatment（C3）performed better; for Xingren Xiaobai Kelou, except for C3 in plots A1 and A2 which had the same yield as C0, most selenium-enrichment treatments（C1, C2, and C4）led to a decrease in yield. The stability of soil pH was high（coefficient of variation CV＜6%）, and there was no regular change in the significant differences in pH values among different selenium-enrichment treatments within the same plot. The soil selenium content increased with the increase in selenium concentration, and the changes in available selenium were complex, related to multiple factors such as variety and soil pH. The selenium content in the seeds of both varieties increased significantly with the increase in selenium concentration. The selenium content of Xingren Xiaobai Kelou was slightly higher than that of Guinan Yi7, and the selenium enrichment coefficient of the seeds increased with the increase in selenium concentration. The selenium content in the grains of the two varieties increased significantly with the increase of selenium concentration. The selenium content of Xingren Xiaobaike was slightly higher than that of Guinong Yi 7, and the selenium enrichment coefficient in the grains of both varieties increased with the increase of selenium concentration. The research suggests that basal application of organic selenium fertilizer is an effective means to increase the selenium content of coix seed, and the higher the concentration, the more significant the selenium-enriched effect. The basal application of C3 concentration selenium-enriched organic fertilizer was the best selenium concentration in this experiment. The selenium content of coix seed in all plots of the two varieties was effectively increased and achieved the ideal selenium-enriched effect, which was comparable to that of the higher concentration C4 treatment. Based on the actual production situation, applying selenium-enriched organic fertilizer with a selenium concentration of 162 mg·kg⁻¹ at the base of coix seed（with an application rate of 4,500 kg·hm⁻²）is the recommended solution for the production of selenium-enriched coix seed products.