[Background] The construction activities in recent decades have caused serious soil and water loss, thus ecological restoration and soil and water conservation of spoil ground are the key projects of environmental protection in construction. The objective of this study is to grasp the improvement effects of 5 legumes (Caragana korshinskii Kom, Trifolium repens L. , Onobrychis viciaefolia Scop, Melilotus suaveolens Ledeb. , and Medicago sativa L. ) at the early stage on the spoil ground in Loess Plateau region of China. [ Methods] Based on field simulation and laboratory analysis, we surveyed soil moisture, nutrient contents and analyzed the correlation among different plant nutrition elements, as well as the improved effects of different plants. [Results] 1) Moisture content of the 0 - 160 cm layer increased with increasing soil depth, the average moisture content of C. korshinskii Kom, T. repens L. ,O. viciaefolia Scop, M. suaveolens Ledeb. , M. sativa L. and control was 17.69%, 15.98%, 17.56%, 18.35%, 17.95% and 14.44%, respectively. In the 0 - 30 cm soil layer, the average moisture content of these plants increased by 77.67%, and in the 30 - 160 cm soil layer increased by 12.78% compared with the control. 2) The mass fraction of nitrate nitrogen of the 5 plants increased compared with the control in the 0 -20 cm soil layer, both ammonium nitrogen and nitrate nitrogen in 0 - 10 cm layer were higher than that of layer 10 -20 cm. And for each plant, the mass fraction of nitrate nitrogen was higher than ammonium nitrogen. In the 0 - 20 cm soil layer, the average mass fraction of available phosphorus under the 5 leguminous plants, ranging from 4.29 - 6.26 mg/ kg, was lower than the control group with 9.01 mg/ kg. In the 0 -20 cm soil layer the average mass fraction of available K was in the range of 130.82 -153.26 mg/ kg, the mass fraction of available potassium reached three levels in the second soil survey. 3) The results of principal component analysis showed that the comprehensive effect of 5 legumes on improvements of soil varied, with the order of T. repens L. >C. korshinskii Kom > O. viciaefolia Scop > M. sativa L. > M. suaveolens Ledeb. [Conclusions] This study found that planting leguminous plants on the abandoned soil field modified the nutrition condition of soil by improving the soil moisture and the mass fraction of nitrate nitrogen. The improved effect of the surface soil moisture content was better than that of deep soil. Planting M. suaveolens Ledeb. increased the soil organic mass (SOM) and available K mass fraction, reduced the mass fraction of ammonium nitrogen and available phosphorus. Other plants showed the consumption of SOM, available phosphorus, and available potassium. By planting legume on the spoil ground, the accumulation of nitrogen surface increased, and soil available potassium content was rich enough to meet the need of plant growth. The result of the comprehensive analysis revealed that the effect of T. repens L. on soil amelioration was the best among the 5 plants.