Abstract: Background Check dams, as essential soil and water conservation structures, are widely used in the gully regions of the Loess Plateau, which suffer from severe soil erosion. Check dams constructed at eroded gully bottoms can intercept sediment from slope areas and promote its deposition within the dam structure. Soil quality assessment is the quantitative evaluation of soil's functional capacity based on a set of key indicators, often integrated into a Soil Quality Index (SQI). The core of this process frequently involves selecting a Minimum Data Set (MDS) of representative soil properties to efficiently and accurately reflect overall soil health. However, the effect of sediment deposition on soil quality after the construction of check dams remains unclear. Methods Using data on soil physical, chemical, and biological properties, this study employed Principal Component Analysis (PCA) and correlation analysis to determine the key factors among these soil properties. Then, the MDS method with the linear and nonlinear scoring models was used to develop an evaluation system for a comprehensive assessment of soil quality in different topographic settings (slope erosion areas and check dam depositional zones) and environmental conditions (dam failure, land-use types, flooding, and soil depth) in the hilly and gully regions of the northern Loess Plateau. Results (1) The MDS identified key indicators of soil quality on the Loess Plateau as soil sand content, pH, organic carbon, inorganic nitrogen, extractable phosphorus, and microbial biomass phosphorus. (2) SQI derived from linear and nonlinear scoring methods using the MDS was significantly higher in check dams than on slopes, by 4.37% (P < 0.05) and 13.97% (P < 0.01), respectively. (3) After a check dam failure, soil quality among various burial types of sediment followed the order: mixed sediment > buried sediment > exposed sediment. (4) Converting land use type from cropland to forest or grassland within the check dam area did not significantly affect soil quality. (5) Flooding decreased soil quality in the check dams, which was higher on the shore than in the water and at the water's edge. (6) Soil quality at different depths showed the highest levels in the 0-20 cm surface layer in the check dam and slope; however, in the deep soil layer (500-1000 cm), soil quality was significantly better in check dams than on slopes. Conclusions This study demonstrates that the process of constructing check dams to deposit eroded soil significantly enhances soil quality within the dam structure, especially in the deep soil layers; besides, dam failure events and flooding also influence the spatial pattern of soil quality. It highlights the positive impact of check dam construction on soil quality, offering vital data and a scientific basis for soil erosion control and ecological restoration on the Loess Plateau.