In order to explore the adaptation mechanism of leaf structure of Salix sclerophylla to cold and high altitude environment, we used the leaf of S. sclerophylla in Jiali County, Naqu, Tibet as experimental material to study the adaptation characteristics of leaf structure of S. sclerophylla to cold and drought environment by paraffin section technology and plant microscopy technology. The results showed that: (1) the leaves of S. sclerophylla willow are heterophylous leaves with epidermis on the back of the leaves. The main veins of the leaves are convex in the lower part of the leaves, showing irregular semicircles. The palisade tissue is arranged in a column, with 2 to 3 layers. The shape of the sponge tissue is mostly short columnar or short spherical, and the cell gap is large. (2) With the increase of altitude, the leaf thickness of the S. sclerophylla willow increased from 40.4 μm at the lowest altitude (4 000 m) to 68.04 μm at the highest altitude (4 700 m). The thickness of the epidermis of the leaves increased significantly between 4 400 m and 4 700 m above sea level, but the thickness of the upper epidermis varies in not significant from 4 000 to 4400 m change. The thickness of sponge tissue and palisade tissue were between 9.34-24.84 μm and 25.63-40.36 μm, respectively. The thickness of sponge tissue and palisade tissue increased with altitude gradient, but change is not significant. (3) There is no stomatal distribution on the upper epidermis of the leaves of S. sclerophylla willow, and a large number of stomata are scattered in the lower epidermis. The stoma density is 17.87-28.37 No·mm^-2, and the total stoma perimeter per unit area is 0.13-0.25 mm, but the stoma density and the total stoma perimeter per unit area have no significant change in the elevation gradient. Studies have shown that the leaves of S. sclerophylla willows mainly adapt to the cold and drought environment in high altitude areas by increasing the thickness of the leaves.