In order to evaluate the effects of organic selenium on selenium enrichment and organic selenium conversion efficiency by selenium application methods，and to optimize the application parameters of organic selenium fertilizer based on fruit quality and yield，in this study，the ‘Junzao’ fruits were treated with different selenium application methods(soil application and foliar spraying)and foliar selenium spraying conditions. The results showed that the application of external organic selenium fertilizer significantly increased the selenium content in ‘Junzao’ fruits. However，when selenium fertilizer was applied to the soil，although the selenium content in the fruits was significantly higher than that in the control group，it didn’t reach the national standard of 0.15 mg·kg-1(dry weight)for selenium-rich fruits. In contrast，foliar spraying gradually increased the total selenium content and the conversion rate of organic selenium with increasing spraying concentrations and frequencies. Specifically，foliar spraying at concentrations of 10，20，30，and 40 mg·L-1，with 3，2-3，and 1-3 applications， respectively，could meet the selenium-rich standard. Under these conditions， the total selenium content was 16-39 times higher than that in the control group，and the conversion rate of organic selenium exceeds 90%. Applying external selenium fertilizer also increased the transverse and longitudinal diameters of the fruits. The maximum increase in fruit size was achieved with soil application at 60 mg·L-1 and foliar spraying three times at 30 mg·L-1，which was 4.8%-15.0% and 4.1%10.2% higher than that in the control group，respectively. Fruit peel hardness and flesh crispness initially increased and then decreased with increasing selenium fertilizer concentrations. When soil application was performed at 60 mg·L-1，the peel hardness and flesh crispness reached their maximum values，which was 17.77% and 15.22% higher than those in the control group，respectively. When foliar spraying was performed three times at 30 mg·L-1，the flesh crispness reached its maximum value，which was 28.3% higher than that in the control group. In different selenium application treatments，the fruit peel hardness was significantly increased by 3.1%-38.7%，compared to that in the control group. The organic selenium fertilizer had varying effects on the nutritional quality of ‘Junzao’ fruits. The contents of soluble solids，total soluble sugar，sugar-acid ratio，vitamin C and soluble protein content in Junzao fruits were significantly increased by 10.8%-46.3%，0.3%-25.9%，2.2%-58.4%，3.6%-26.0% and 1.2%-30.5%，respectively，while the content of titratable acid was significantly decreased by 2.9%-20.2%. When soil selenium fertilizer was applied at a concentration of 60 mg·L-1，the average fruit weight，average number of fruits per plant，and yield were maximized，with increases of 9.5%，9.9%，and 20.3%，respectively，compared to those in the control group. For foliar spraying，these values were maximized when three sprays were performed at 30 mg·L-1，with increases of 20.0%，19.2%，and 43.2%，respectively，compared to those in the control group. The study showed that foliar spraying of selenium fertilizer was more effective than soil application in improving fruit quality and increasing selenium content and yield. The optimal method was to perform three foliar sprays at a concentration of 30 mg·L-1. The research results could provide references for key technical measures in the production of selenium-enriched jujubes.