Abstract: A field experiment of different N application rate to mustard was carried out. The results showed that, under the condition in this experiment, with the increase of N application amount,the mustard yield appeared a trend of increasing first and then lowing down. When the nitrogen rate per 667 m² was 20.96 kg (314.40 kg/hm²), the yield was the highest of 4452.7 kg(66790.50 kg/hm²), and when the nitrogen rate was 19.71 kg (295.65 kg/hm²), the economic benefit was the highest of 3318.78 yuan (49781.7 yuan/hm²).