Abstract: To explore the response mechanism of biomass allocation pattern and the rational fertilization of Avena sativa‘Qingyin No.1’, different nitrogen treatments were set up. The results showed that nitrogen had significant influence on the biomass accumulation and distribution of various organs of‘Qingyin No.1’. The maximum biomass accumulation of stems, leaves, panicles, roots and total biomass was 1332.97, 375.53, 587.52, 205.20 and 2501.22 g/m2 respectively under 75 kg/hm2 nitrogen application amount. The higher biomass distribution of stems, leaves, panicles and roots was obtained under the nitrogen application amount of 30, 60-90, 90-120 and 0-60 kg/hm2, respectively. The total biomass, the biomass of stems and roots increased first rapidly and then slowly with the advancement of reproductive period, while the biomass of leaves first increased and then decreased. But the panicle biomass increased continuously. The order of biomass distribution pattern of milk- ripe stage was stems＞ panicles＞ leaves＞ roots. There were allometric relationships between root and stems, panicles, leaves under different nitrogen treatments. The biomass accumulation of stems and panicles was higher than that of root, while the biomass accumulation of leaves was lower than that of root. The morphological plasticity of different organs of‘Qingyin No.1’under nonfertilization was higher than that under fertilization.