Abstract: Agronomic traits such as yield, quality and nitrate content of gramineous forages are closely related to nitrogen level. Field experiments were conducted to study the effects of six urea application levels and four application methods on the agronomic traits, yield, quality, and nitrogen producing efficiency of ryegrass. Correlations among yield, crude protein content, amino acid content, N application amount and many agronomic traits were also investigated. Tiller number, plant height, yield, crude protein content, amino acid content and nitrate content significantly increased with increasing N application. However, effects of N application on ryegrass became less and nitrogen production efficiency became low with further increasing N application amounts. When N application was over 100 kg/hm² after each cutting, N fertilizer increased crude protein content but had little influence on amino acid content. When N application reached 250 kg/hm² after each cutting, plant height and yield showed decreasing trends. When N application was over 150 kg/hm², nitrate N content increased significantly, and even exceeded the 25% poisoning criterion. There were positive correlations among yield, plant height, tiller number, crude protein content, and nitrate N content of ryegrass. The yield was significantly correlated with the N application amount of broadcast applications. Crude protein and amino acid content were significantly or extremely significantly correlated with N application amount. Moreover, there was an extremely significant correlation between nitrate content and N application amount. Deep application influenced tiller number and plant height, and increase yield, crude protein and amino acid content.