Abstract: Although the range of distribution of Jinshajiang dry-hot volley is not universal, it has a very important influence on ecological environmental quality of Jinshajiang watersheds and is the key area in the construction of Jinshajiang e-cological environment. Due to the characteristics of extremely hot and dry climate, it is hard to build the artificial eco-forest. The environmental determination in the typical sector of dry-hot volley Yuanmou showed that the forest s micro-environment of the existing arboreous eco-forests was not good. The irradiation intensity, the daily average value of air-temperature (27.37℃) and the surface soil temperature (32.54℃) in forest F_an was only 20.7%, 0.14℃and 3.31℃ less than open field respectively. The average soil moisture of 0 - 100 cm soil layer in F₁, F₂ and F₃ in spring was 6.84%, 5.83% and 9.16%. It was only 9.83% in forest F_an also. The soil moisture of natural grass slop with Cheteropogoh cantortus community in this season was 13.20% in comparison with the artificial eucalyptus forest. As a result, the trees grew slowly. Take the ten-year-old forest (Form Eucalyptus camaldulensis) for example, the average tree height in the forest F₁ was 9.46 m and the average diameter at breast height 8.68 cm; on the contrary, the average height in the forest F₂ was only 7.22 m and average diameter was even smaller (3.97 cm) . The growth of trees in larger density forest wasn' t evidently normal. The optimum forest structure couldn' t be built in the high density artificial arboreous eco-forest in dry-hot volley area. The growth status of sparse trees and disperse trees was all right.