In recent years，the scale of conventional rice planting in the double-cropping rice area has been continuously expanding.At the same time，excessive application of nitrogen fertilizer is also a prominent problem in production. Therefore，it is of great significance to study the nitrogen reduction effect of fertilizer recommended by nutrient expert system in the double-cropping conventional rice planting mode.The experiment was carried out in Wenzhen Town，Jinxian County，Jiangxi Province in 2019 and 2020.Early and late rice varieties were conventional rice varieties，Jiangzao 361 and Xiangwanxian 12，respectively.A total of six treatments，including fertilizer recommended by nutrient experts(NE)，no nitrogen fertilizer treatment(NE-100%N)，nitrogen fertilizer reduction by 25% and 50%(NE-25%N and NE-50%N)，nitrogen fertilizer increased by 25% and 50%(NE +25%N and NE+50%N)were set up，and rice yield，plant nitrogen，phosphorus and potassium nutrient uptake，nitrogen utilization efficiency and other indicators were measured.The results showed that the two-year early and late rice yields and nitrogen fertilizer yield response were the highest in the NE treatment，which significantly increased the yield by 11.6%～59.3% compared with the NE-100%N and NE-50%N treatments.With the increase of the nitrogen amount，the yield reached the highest at the NE treatment，and when nitrogen continued to increase，the rice yield had a decreasing trend.Further calculation of the fitting equation showed that there was a very significant one-variable quadratic parabola relationship between yield and nitrogen application rate.Nitrogen application rates for early and late rice in the two-year NE treatment were reduced by 13.7%～18.2% and 6.7%～12.5%，respectively，compared with the optimal nitrogen rate，and the yield was slightly higher than the corresponding yield of the optimum nitrogen application rate.The nutrient uptake of nitrogen increased with the amount of nitrogen applied，and reached the highest in NE treatment.The two-year average nitrogen uptake of early and late rice was significantly increased by 9.5%～105.7% and 7.0%～88.0% compared with other treatments，respectively.The average nitrogen uptake efficiency of early and late rice with NE treatment increased by 14.7%～147.0% and 8.9%～155.0%，respectively，compared with the other treatments in two years. The average agronomic utilization of NE treatment had no significant difference than that of NE-50%N and NE-25%N treatments.，and the increase was 27.9%～108.2% compared with the other treatments in two years.In summary，the amount of nitrogen fertilizer recommended by nutrient expert system can increase the yield of double-cropping conventional rice，increase the nitrogen nutrient uptake of rice plants and the utilization of nitrogen fertilizer，and at the same time achieve the goal of reducing nitrogen and increasing efficiency，which is conducive to scientifically guiding the application of nitrogen fertilizer for double-cropping conventional rice.