Abstract: The dry matter accumulation and grain and straw yield of Baiyan No. 2 under different sowing dates and fertilization levels were studied to determine the optimal sowing date and suitable fertilization amount of oat during the critical period of water requirement and the rainfall abundant period in this area. The trend diagram of dry matter accumulation in different period of oat growth process was drawn and the graph was S - shaped curve. The dry matter accumulation, grain and straw yield of oat under various treatments were comprehensively analyzed and found that under different production purposes,the combination of agronomic measures could increase the yield of grain and straw by adjusting sowing date and fertilization level. It could be seen that if the application of pure nitrogen in agronomic measures could be in the range of 66.85-78.11 kg/hm^2 and the application of pure phosphorus could be in the range of 31.90-37.05 kg/hm^2 grain yield of more than 2 600 kg/hm^2 can be harvest by sowing on May 28 to 29.