The field experiment was conducted to study the effect of different nitrogen fertilizer management on dry matter accumulation and yield of maize under plastic-film mulching in the semi-arid region of western Jilin Province. The result showed that reasonable postponing nitrogen application increased dry matter accumulation and yield of maize by 12.18% and 12.75%, and nitrogen agronomic efficiency and partial factor productivity under plas-tic-film mulching, increased by 7.42 kg/kg and 7.42 kg/kg. The recommend nitrogen fertilizer management formulafor the highest yield（11 805 kg/hm²）, dry matter accumulation and agronomic efficiency was 1/3 nitrogen fertilizer ap-plied as basic fertilizer, 1/3 as jointing fertilizer, 1/6 as tasseling fertilizer and 1/6 as filling fertilizer under the total nitrogen application of 180 kg/hm² in the semi-arid region of western Jilin Province under plastic-film mulching.