[Objective] In order to improve soil structure of the subsoil layer of black soil and solve the problem of how to return maize straw in Northeast China, a three-year (2015—2018) field experiment was carried out.[Method] The field experiment was designed to have three treatments in returning pattern, i.e. CK (no straw return), QS (returning of chopped straw) and KL (returning of pelletized straw), and three treatments in straw returning dosage, i.e. low dosage (15 000 kg·hm^-2), medium dosage (45 000 kg·hm^-2, 3 times as much as the low dosage) and high dosage (75000 kg·hm^-2, 5 times as much as the low dosage), and all had the straw buried in the soil 30-40 cm depth. Effects of the treatments on soil bulk density, soil compactness and soil water content were explored, and effects of soil aggregate distribution regulating soil physical properties was analyzed.[Result] The tests of the soil samples collected at the maize maturity stage of the three year experiment show:1) The practice of deep straw returning reduced soil bulk density and soil compactness and increased soil water content, and the effects were more significant in the 20-40 cm layer than in the 0-20cm soil layer. Moreover, the effects become more significant with increasing of straw dosage, and less with the time going on, and the effects of straw returning once at a high rate might last for a few years. In the third year of the experiment, only QS5 reduced soil bulk density significantly or by 10.9% (P < 0.05), and QS5 and KL5 lowered soil compactness by 24.1% and 22.0% (P < 0.05), but raised soil water content by 8.9% and 7.4% (P < 0.05), respectively; 2) The treatments of medium and high in dosage significantly increased the content of macroaggregates and reduced the content of microaggregates in the subsoil, and the fractions of > 0.25 mm water stable aggregates and of the > 2 mm large aggregates increased significantly with rising straw dosage. What's more, the return of pelletized straw tended to promote the formation of macroaggregates than the return of chopped straw. The first and second years of straw returning were the main period for formation of macroaggregates, of which the highest content reached up to about 5 times and 1.5 times than that in CK, respectively; 3) Significant relationships were observed of 0.25-0.053 mm micro aggregate and > 0.25 mm water stable aggregate with soil bulk density, soil compactness and soil water content in the subsoil layer (P < 0.05), and the 0.25-0.053 mm, > 2 mm, and > 0.25 mm fractions of aggregates were the key factor driving changes in soil physical properties in 2016 and 2017, but the 1-0.5 mm fraction of aggregates was found to be the key factor driving the changes in soil physical properties in 2018.[Conclusion] Therefore, from the perspective of recycling maize straw in Northeast China, the return of chopped straw with a rate of 75 000 kg·hm^-2 is a good management to regulate the distribution of soil aggregates and improve the physical properties of subsoil. The finding may provide a theoretical basis and technical guidance for improvement of soil structure of the black soil in China.