It is one of the most important roles of soil in hilly and gully loess regions to reduce or control soil and water loss. The soil samples were taken from 0～50 cm soil at an interval of 10 cm in permanent grassland, 20-year, 8-year and 3-year farming-withdrawn grasslands, 3-year artificial grassland and farmland (Control). Twelve representative soil parameters were chosen to screen the main factors affecting soil quality by factor analysis, and therewith analyze the soil quality evolvement of grassland. The results showed that, soil quality mainly depended on the factors concerned with soil humus, water and soil conservation and soil mechanics. Permanent grassland showed the best humus conditions in 0～10 cm soil and its soil upper layers were better than its lower layers in humus conditions. Compared with farmland, farming-withdrawn grasslands presented greatly increased soil humus, especially in 0～10 cm soil. 3-year farming-withdrawn grassland had better humus conditions in the soil layer spanning from 20 to 50 cm than the other farming-withdrawn grasslands. Grasslands clearly got their soil- and water- conserving capability improved, and the improvement in their water- and soil-conserving capability become weak with increased soil depth. The longer the grasslands were withdrawn from farming, the better they conserved soil and water. Farmland showed the poorest mechanical soil properties in 0～10cm soil and this was mainly because soil tillage damaged soil cohesion. Because of its loose soil conditions, permanent grassland presented poorer mechanical properties than farming-withdrawn grasslands did. Permanent and 20-year farming-withdrawn grassland showed the ablest soil quality in 0～10 cm soil among the various lands, and their soil quality declined with soil depth. Farmland showed the poorest soil quality in the soil layer spanning from 40 to 50 cm and 0 to 10 cm, but the reasons for the poorest soil quality differed between them, the former poor quality resulting from poor humus conditions and the latter being caused by poor soil and water conservation and poor soil mechanical properties. 3-year farming-withdrawn land presented slightly different qualities among different soil layer. Both farming-withdrawn and artificial grasslands got notably improved in soil quality, especially in 0～20 cm soil. Soil quality of farming-withdrawn grasslands got improved in 0～10 cm soil layer as the farming-withdrawing period continued. Under the same farming-withdrawing period (3 years), farming-withdrawn grasslands presented better soil quality than artificial grassland, but the latter capability of soil and water conservation was notably superior to the former’s. This suggested that it should be an effective approach of controlling water and soil losses in the regions to construct artificial grasslands.