Selenium is a necessary trace element for the human body. As people’s understanding of selenium products gradually deepens，more and more selenium-rich foods appear on the market. In this study，the Leling Ziziphus jujube was used as the object，and the nano meter selenium fertilizer was sprayed on the foliar surface of the jujube in the young fruit stage，fruit expansion stage，and color transformation stage to explore the effects of different concentration gradients (0，4.8，9.6，14.4 mL/L) of nano meter selenium fertilizer on the yield and quality of jujube. The results showed that the foliar application of nano meter selenium fertilizer significantly increased the yield and quality of Ziziphus jujube. With the increase of selenium concentration，the selenium content in Ziziphus jujube fruit gradually increased，but the yield first increased and then decreased. The foliar application of selenium fertilizer significantly increased the contents of soluble solids，vitamin C and mineral elements in jujube fruit and leaves. The best effect was occurred when treated with 9.6 mL/L selenium，the yield increased by 33.0%，the soluble solids increased significantly by 8.4%，the content of vitamin C increased significantly by 53.5%，and the content of selenium in jujube fruit reached 0.28 mg/kg，with a significant increase of 171.8% compared with the blank control. The content of mineral elements，such as phosphorus，potassium，calcium，magnesium，boron，and iron，increased most significantly. Comprehensive analysis shows that the effect of increasing the yield and quality is best when the concentration of nano meter selenium fertilizer is 9.6 mL/L with foliar application.