The effects of nano-carbon water-retaining fertilizer on yield, quality of tuber mustard, and fertilizer utilization efficiency were studied with the field experiments compared to the local tuber mustard fertilizer with equal amount of effective composition. The results showed that the yield of tuber mustard was 50 670—56 496 kg/ha in treatments of nano-carbon water-retaining fertilizer decreasing by 10%—40%, and compared with local tuber mustard fertilizer, the average yield was increased by 94.8%. The yield increasing rate of tuber mustard was 93.0% in treatment of nano-carbon water-retaining fertilizer decreasing by 30%. The average fertilizer utilization efficiency of nitrogen and phosphorus was 54% and 39.7%, respectively, the average increment of fertilizer utilization efficiency was 36% and 37%, respectively compared with local tuber mustard fertilizer. Especially in treatment of reducing nano-carbon water-retaining fertilizer by 30%, the nitrogen and phosphorus fertilizer utilization efficiency was increased by 64% and 56%, respectively. By comprehensive comparison, it was found that nano-carbon water-retaining fertilizer and the treatment of 30% reduction could significantly improve the yield of tuber mustard and fertilizer utilization efficiency, and have popularization and application value in the Three Gorges Reservoir area.