Reseeding with native species enhances grassland yield and forage quality while minimizing disruption to original vegetation in degraded desert steppes of arid regions. However, the mechanisms by which long-term reseeding influences plant community stability remain unclear. Five native species-Agropyron desertorum, A. mongolicum, Lespedeza pataninii, Astragalus laxmannii, and A. melilotoides-were reseeded in a degraded desert steppe in arid Northwest China, with naturally enclosed grassland as control (CK). Six reseeding combinations maintained a 2:1 seed weight ratio between graminoid and leguminous species. Plant and soil properties were analyzed to elucidate vegetation dynamics and community stability. Key findings: 1) The results indicated that the control group (CK) yielded the highest species diversity index (2.36), albeit without significant differences compared to the treatments (P > 0.05). Furthermore, the diversity index of the three-species combinations (reaching a minimum of 2.09) was generally superior to that of the two-species combinations (maximum of 2.08). All reseeding treatments were found to significantly enhance quantitative vegetation characteristics relative to CK. 2) The functional richness index (FRic) was highest (10.62) in the A. desertorum + A. mongolicum + A. melilotoides treatment. The functional evenness index (FEve) reached a maximum value of 0.85 in the A. desertorum + A. mongolicum + L. pataninii combination. With the exception of the A. mongolicum + A. laxmannii treatment, which had a functional dispersion index (FDis) of 2.10, all other treatments exhibited higher FDis values than CK (2.18). 3) The A. desertorum + A. mongolicum + L. pataninii combination exhibited significant negative associations, whereas A. desertorum + A. mongolicum + A. melilotoides demonstrated significant positive associations. With the exception of the A. desertorum + A. mongolicum + A. laxmannii (1.17) and A. mongolicum + A. laxmannii (1.67) treatments, which had a positive-to-negative association ratio >1, negative interspecific associations predominated (ratio <1) in all other treatments. 4) Species diversity correlated strongly with soil total nitrogen, available potassium, total phosphorus, and bulk electrical conductivity; functional diversity and interspecific associations linked primarily to soil water content and total nitrogen. 5) Although reseeding did not directly enhance stability, indirect improvements were mediated through functional diversity and soil properties, with A. desertorum + A. mongolicum + A. melilotoides identified as the optimal combination for rehabilitation. Different grass species combination reseeding reshapes community structure and reinforces soil-plant feedbacks, providing a mechanistic basis for restoring ecological stability in degraded arid steppes.