Grassland in the dry and warm valley of Dadu River plays an important role in vegetation coverage restoration and natural succession of plant communities, while soil quality plays a key part in vegetation restoration. In this study, we divided the slop direction into 8 types (North, Northeast, East, Southeast, South, Southwest, and Northwest) in the Luding-Hanyuan section of the dry warm valley of the Dadu River. The soil physical properties as well as the soil chemical properties of the grassland with different slope directions was analyzed, and the grass coverages with different slope directions of grassland was also investigated, furthermore, the soil quality of dry and warm valley of Dadu River was assessed by principal component analysis. The results show that the minimum data set affecting soil quality of dry and warm valley grassland are non-capillary porosity, soil bulk density, organic content and C/N ratio. In the dry warm valley of Dadu River, the soil quality gradually decreases from the northeast slope to the southwest slope due to the hot and dry microclimate, which leads to more intense soil mineralization. The stable sunshine time and appropriate water conditions on the north slope are advantageous to potassium and phosphorus release in the soil. There was a positive correlation between vegetation coverage and soil quality and soil quality decreased with the decreasing of vegetation coverage. The soil quality of high vegetation coverage (> 70%) is mainly affected by noncapillary porosity, while that of low and high coverage grassland (< 30%) is mainly affected by soil bulk density. The middle value of grassland soil quality index is more distributed in the dry and warm valley of Dadu River, and the soil fertility is in the middle level of 2-4. The soil quality of the grassland is better as a whole in the dry and warm valley of Dadu River, and potential in fertility of grassland is high, which is conducive to plant growth and positive succession of plant community.