Total nitrogen (TN), as one of the cementing substances formed by soil aggregates, can accelerate the transformation among aggregates with different particle sizes. Taking the Wangmaogou small watershed in the Loess Plateau as the research object, the "S" method and the digging section method were used to sample the 0-60 cm soil of slope farmland, grassland, shrubland, forest and terraces. The slope farmland was used as a control to explore the stability of soil aggregates and their TN content under four ecological constructions. The TN contribution rates of soil aggregates were analyzed for different depths (0-20, 20-40, 40-60 cm) and different particle sizes (> 5, 5~2, 2~1, 1~0.5, 0.5~0.25, < 0.25 mm). The results showed that ecological construction significantly increased the content of large soil aggregates. Compared with grassland and forest, the aggregates of > 5 mm in the surface soil were increased by 469% and 438% respectively, and the stability of soil aggregates (MWD, GMD) were increased. In the vertical direction, the stability of the aggregates decreased with the increasing depth. Compared with sloping farmland, grassland, shrubland, forest and terraces could increase the TN content of soil aggregates to varying degrees. Among them, forest aggregates had the highest TN reserves (36.53 kg/m²), and the TN reserves in the shrubland (32.12 kg/m²), grassland (20.30 kg/m²) and terraces (18.62 kg/m²) were increased by 131%, 46% and 34% respectively compared with slope farmland. With the increase of soil depth, the influence of different ecological construction types on aggregate TN content gradually was weakened. With the natural succession process of sloping farmland-grassland-shrubland-forest, the contribution rate of TN by aggregates of < 0.25 mm showed a decreasing trend. Terraced fields could improve the soil structure of sloping farmland to a certain extent. With the particle size range of 5~0.25 mm, the TN content of soil aggregates could reach the level of grassland recovery, but the aggregates of > 5 mm had still relatively large space for recovery.