In the context of global warming, how plants adapt to changes in environmental factors has become one of the hot topics in ecological research in past decade. Leaves, as the organs with the largest surface area exposed to the sun and air, are the most important place for the exchange of energy and mass between plants and the atmosphere, and are also considered to be the link between plants and the environment. Leaves are very sensitive to environmental changes, and usually show differences in external morphology, epidermal characteristics and anatomical structures with changes in the environment (temperature, solar radiation etc), which can reflect the survival strategies formed by plants adapting to environmental changes. The Qinghai-Tibetan Plateau is one of the most sensitive areas responding to climate change in the world because of its unique topography, and the change of altitude gradient will correspond to the variations of various environmental factors, especially the temperature. Therefore, it has become an ideal place to study the adaptation of leaf traits to environment. In order to examine the responses of leaf traits of alpine plants to altitude changes, the paraffin section method and microscopic techniques were used to study the external morphology, epidermal and stomatal characteristics and anatomical structures of the leaves of Leontopodium nanum from five different altitudes from 3400 m to 4200 m in Lenglong Ling (Ridge), northeast of the Qinghai-Tibetan Plateau, and the changes in leaf traits with altitude were investigated. The results showed that:(1) when the altitude increased, the leave of Leontopodium nanum tended to be reducing in size, while the specific leaf weight and leaf dry matter content showed an increasing trend; (2) the stomatal density of lower epidermis was first up and then down with the increasing altitude, and there were significant correlations among stomatal characteristics such as stomatal density, stomatal apparatus area, stomatal length, stomatal width and potential conductance index; (3) leaf thickness, palisade and spongy tissue thickness increased significantly with increasing altitude; (4) leaf anatomical plasticity showed that the upper and lower cuticle thickness had the largest plasticity index, and there were significant correlations among some anatomical traits according to the correlation analysis. The results of this study suggested that the Leontopodium nanum had chosen the strategy by producing smaller and thicker leaves in order to adapt to decreasing ambient temperature with the increasing altitude, which can help itself to resist cold environment, improve water use efficiency, and maximize access to resources in plant growth and development, and then to prolong its life span and benefit its survival in the cold alpine environment.