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Shrubs play different key roles in arid regions. Comparisons of shrubs and their site adaptability are essential for correct selection of candidates in developing restoration theory and practice. A survey of topography, soil properties and shrub composition was conducted in fifty-seven 5-m x 5-m plots in an arid valley of the upper Minjiang River, Southwest China. With cluster analysis and critical examinations based on edaphic properties, soil was classified into three groups: dry cinnamon soils (DCS), calcareous cinnamon soils (CCS) and eluvial-accumulation cinnamon soils (EACS). EACS had the highest fertility level, DCS the next and CCS the lowest level. For non-N fixers, soil moisture is the primary limiting factor, and nitrogen the next. However, N-fixers are weakly constrained by soil moisture and nitrogen, the extent of which is species-specific. N-fixers had a significantly higher cumulative relative importance value (44.4%) in CCS than in DCS (34.0%) and EACS (17.3%). The results suggest that it would be reasonable to restore non-N fixers in DCS and EACS and that N-fixers are appropriate for CCS. Compared with grass, shrubs significantly enhanced the availability of nitrogen and phosphorus and soil electric conductivity, and significantly decreased the soil C/N ratio. The median fertility level of soil dominated by N-fixers indicates that N-fixers are suitable driver candidates from grassland to non-N-fixing shrub land. Four native shrubby legumes (Indigofera amblyantha, Sorphora viciifolia, Desmodium podocarpum and Bauhinia faberivar) and one soil-conserving shrub (Ajania potaninii) are the top-priority pioneers for ecological restoration.