Abstract:An eco-anatomic study on leaves and woods of Fagus lucida Rehd. et Wils., which grows at an elevation of 1 260～2 020 m above sea level in Mountain Fanjingshan, Guizhou Province of Southwestern China, was carried out. Anatomical characteristics of leaves (including the thickness of upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis and lamina) and woods (vessel length, vessel width, vessel frequency, fiber length, ray width, ray height and ray frequency), and leaf surface characters (stomatal density, stomatal width and stomatal length) were determined and compared along the latitudinal gradient. As the results, 1) Lamina thickness was between 119.2 and 364.3μm; 2) Vessel frequency 75.2～133.6 per mm , vessel width 50.7～85.6 μm, vessel length 479.8～748.6 μm; fiber length 936.4～1 326.9 μm; total frequency of single and muhiseriate rays 6～9 per mm; 3) No solitary trichome was found on mature foliage, and the stomatal density was 72～113.6 per mm . Climatic indices at different altitudes were obtained by means of climatological method. Multi-statistical analysis was used to clarify the relationship between the morphological characters of the leaves and woods and climatic factors. The results showed that: 1 ) The thickness of palisade mesophyll, lower epidermis and lamina, and the vessel width increased with the humid/ add index (Bailey’s index); 2) With an increase of annual precipitation, spongy mesophyll thickness, vessel length and fiber length increased, but vessel frequency and stomatal density decreased; 3) Morphological features of leaves were closely related to low winter temperature, namely, lamina thickness decreased with coldness index, and the stomatal size decreased as the increase of mean temperature of the coldest month.