This study aims to investigate the effects of acidified zeolite (SF) on nitrogen leaching and nitrogen use efficiency of grain under the condition of urea reduction. The adsorption properties of acidified zeolite for NH₄⁺—N and NO₃^-—N, and the effects of acidified zeolite on nitrogen leaching and nitrogen utilization under different nitrogen application gradients were studied by isothermal adsorption test, soil column leaching, and maize pot experiment. Three nitrogen reduction gradients were set up, i.e., farmers' conventional fertilization (CN), nitrogen reduction by 15% (CN1), nitrogen reduction by 30% (CN2), and 0.2% acidified zeolite was added to the three nitrogen reduction gradients (CN+SF, CN1+SF, and CN2+SF), respectively. The results showed that the maximum adsorption capacities of NH₄⁺—N and NO₃^-—N by acidified zeolite were 25.44 mg/g and 31.59 mg/g, respectively. The adsorption process could be well fitted by Langmuir model. When nitrogen was reduced by 15% and 30%, the cumulative leaching loss of NH₄⁺—N with acidified zeolite was 7.10% and 8.76% lower than that of CN1 and CN2, respectively. Acidified zeolite could effectively adsorb NO₃^-—N only when nitrogen was reduced by 30%. The cumulative leaching loss of NO₃^-—N was 15.90% lower than that of CN2. The acidified zeolite could effectively improve soil nitrogen content and nitrogen use efficiency of maize grain. Compared with urea application (CN, CN1, and CN2), adding acidified zeolite (CN+SF, CN1+SF, CN2+SF) increased nitrogen use efficiency of grain by 10.37%, 20.79%, and 47.14%, respectively. Under the condition of reducing the use of urea, acidified zeolite can effectively reduce soil nitrogen leaching, improve nitrogen use efficiency of maize, and has potential agronomic value.