As one of the essential elements for the growth and development of crops, nitrogen is involved in the synthesis of various nitrogenous organic substances in plants and plays an important role in their growth and development. Therefore, it is important to study the optimal application of nitrogen fertilizer for high quality and high yield of pepper and soil protection of farmland. To investigate the effect of silicon application on yield, fruit quality and nutrient uptake and utilization of pepper at different levels of nitrogen supply, the pepper variety "Audrey" was used as the test material and was grown in substrate with normal nitrogen fertilization (1.0N: 260.9 kg/667 m2), reduced nitrogen fertilization by 40% (0.6N: 149.1 kg/667 m2), reduced nitrogen fertilization by 60% (0.4N: 104.3 kg/667 m2), and no nitrogen fertilization (0N: 0 kg/667 m2)., and two levels of silica fertilizer (0 mmol/L, 1.5 mmol/L), to study the effect of silicon on nitrogen uptake and utilization and fruit quality of pepper crop under different levels of nitrogen supply, and to screen out the best fertilization treatment, aiming to provide a theoretical basis and technical reference for increasing yield and improving quality of facility pepper. The results showed that: (1) Fruit yield of pepper at 0.6N N supply level increased by 7.18%, 74.14% and 87.99% compared to that at 1.0N, 0.4N and 0N N supply levels, respectively, and silicon application further promoted fruit yield, where silicon application at 0.6N N supply level increased fruit yield of pepper by 15.33% compared to that at normal N supply level. (2) The 0.6N nitrogen supply level was more favorable to promote the increase of soluble sugar, reducing sugar, soluble protein and vitamin C content and decrease of titratable acid and NO3- content in pepper fruits, and the soluble sugar, reducing sugar, soluble protein and vitamin C content in pepper fruits at 0.4N and 0N nitrogen supply levels were significantly lower than those at 1.0N and 0.6N levels, and the quality of pepper fruits was significantly improved after silicon application. The fruit quality of pepper at different levels of N supply was significantly improved. (3) The 0.6N N supply level was more beneficial to the accumulation of mineral elements in pepper fruits and the improvement of soil N fertilizer utilization, in which the N fertilizer utilization and N fertilizer agronomic efficiency were significantly increased by 97.57% and 69.20%, respectively, under 0.6N supply level compared with 1.0N supply level, and the mineral elements content of pepper fruits and soil N fertilizer utilization were significantly increased under different N supply levels after silicon application. (4) The results of principal component analysis of pepper yield and fruit quality indicators showed that the highest overall score was obtained under 0.6N+Si treatment, other words, the application of exogenous silicon fertilizer of 1.5 mmol/L with 40% reduction of N fertilizer had the best effect on N fertilizer uptake and utilization, fruit mineral element accumulation, fruit quality and yield of pepper.