Abstract: Aiming at the problems of excessive and unreasonable fertilizer application, lower nitrogen use efficiency, increasing N₂O emission from soil and fertilizer in current intensified agricultural productions, a field experiment was conducted to study the effects of dicyandiamide (DCD) combined with nitrogen fertilizer application at different levels, i.e., 150, 225, 300 kg·hm^-2, on N₂O emission and relevant economic benefit in a typical winter wheatsummer maize rotation system in North China Plain. The results showed that DCD application decreased N₂O emission fluxes and cumulative emissions by 25.6%-32.1% and 23.1%-31.1% in the yearround. There was a significant positive exponential correlation between N₂O flux and soil surface temperature or soil moisture content. The effect of soil moisture on  N₂O emission was stronger in wheat season than in maize season, while the effect of temperature on N₂O emission was on the contrary. The yields of winter wheat and summer maize with DCD addition were increased by 16.7%-24.6% and 29.8%-34.5%, respectively, and the average economic income of two seasons was increased by 7973.2 yuan·hm^-2. Therefore, appropriate rate of N fertilizer combined with DCD could not only increase crop yield and economic income, but also reduce N₂O emission. Considering environmental and economic benefit under this experimental condition, DCD combined with nitrogen of moderate level (total N amount 225 kg·hm^-2) was a good nitrogen management mode in North China.