Abstract: Background Dry-hot valley is one of ecologically fragile areas and it is also a difficult strip for vegetation recovery. Forest vegetation plays an important role in reducing water loss and soil erosion, sand prevention, and improving the deteriorating ecological environment. Methods We combined the method of the field investigation and indoor analysis to measure the main physical and chemical properties of six types of different woodlands (Pinus armandii + Coriaria nepalensis + Lolium prenne, P. armandii + Larix gmelinii, Juglans regia, P. armandii, Zanthoxylum bungeanum, and Morus alba) and farmland in the dry-hot valley of Qiaojia County. The study also used a method of the subordinate function evaluation to evaluate the effects of the soil improvement for six kinds of forests, which aimed to provide scientific basis and practical reference for the selection of ideal forest types for the project of returning farmland to forest. Results The results showed: 1) Soil structure of different woodlands was improved to some degree and soil nutrients were further improved, and moisture content, total porosity, capillary porosity, organic matter, total N, total K and available K decreased with the increase of soil depth between different woodlands,while the soil density showed an opposite trend. In addition, soil density, moisture, organic matter, soil total nutrient and available nutrient all showed an order of mixed forest of trees, shrubs and grasses > mixed trees forest > pure forest. 2) The evaluation on effects of the soil improvement of six kinds of typical forests showed: Pinus armandii + C. nepalensi + L. prenne > P. armandii + L. gmelinii > P. armandii > farmland > M. alba > J. regia > Zanthoxylum bungeanum. Conclusions On the whole, the effects of soil improvement were obvious since the project of returning farmland to forest. P. armandii + C. nepalensis + L. prenne had the best effects of soil improvement while P. armandii + Larix gmelinii ranked the second. Among the pure forests, P. armandii had the highest effect of soil improvement, J. regia and M. alba were roughly the same, and Z. bungeanum was the lowest. P. armandii + C. nepalensis + L. prenne (mixed forest of trees, shrubs and grasses) was an ideal model for soil improvement in the local area, which was suitable for promotion in the dry-hot valley area. We suggest that evaluation of the effects of soil improvement should be carried out from time to time so as to increase the soil uptake of N and P to improve the local ecological environment.