In order to improve black soil productivity in the Songliao Plain Cornbelt, a new tillage technology “deep plowing with mulching” was established. The effects of different tillage systems (deep plowing with mulching, subsoiling tillage and conventional tillage) on soil profile construction and aggregate stability were studied in this paper. The results showed that different tillage systems led to different patterns of soil profile construction; the deep plowing with mulching, subsoiling tillage and conventional tillage formed “flat type”, “undulated type” and “groove type” in the interface between plow layer and plow pan, respectively. Compared with subsoiling tillage and conventional tillage, deep plowing with mulching significantly increased the contents of macroaggregates, and decreased the aggregate deterioration rate in the plow layers. This work demonstrates that the new tillage technology could promote soil aggregate stability and contribute to soil structure improvement in the Songliao Plain Cornbelt, China.