To explored the effects of different nitrogen application levels on the root morphology and maize yield under straw deep burial in salinized arableland，a 2-year field experiment was carried out in Hetao Irrigation District. The experiment included fivetreatments:CK(controlgroup)，N 0(no nitrogenapplication)，N 1(135 kg·hm -2)，N 2(180 kg·hm -2)，and N 3(225 kg·hm -2). Maize root samples werecollected at jointingstage，silking stage and maturity stage. The results showed that under the condition of strawdeepburial，in the whole growthperiod，compared with the treatmentwithout nitrogenapplication(N 0)，the total rootlength，root surface area and rootvolume increased by67.65%，86.71%and62.95%，respectively. The average root dry weight was increased by 94.63% and the average root shoot was increased by 16.43%. Although the overapplicationofnitrogen(N 3)promoted the root system in the 40 -60 cmsoillayer，it still inhibited the root system in general. Compared with N2treatment，the total root length，root surface area and root volume of the growth period werereduced by12.45%，17.48% and18.07%，respectively. The average root dry weight was reduced by 11.68% and the average root shoot ratio was reduced by 8.22% in the two years of N3treatment. Compared with the controltreatment， the 2-year average yield of N2 treatment was increased by 4.96%. The optimal nitrogen application level for maize in Hetao Irrigation District was 180 kg·hm-2. The results can provide a theoretical basis for optimizing the nitrogen application level of maize tillage and improving the utilization of straw resources in salinized arable land.