Abstract: This paper deals with the species diversity of pteridophytes from the Laojun Mountain Nature Reserve based on taxonomic and floristic studies. The results show: (1) Richness in pteridophytes species demonstrated by the following large species diversity indices, Dmg index 17.9, Dmn index 2.1, Dri index 41.1 and Dsi index 0.98; (2) High species density (0.02 species / m2) and high individual density (0.6 individual / m2) of pteridophytes; (3) The species occuring most frequently are Alsophila costularis (50.0), Egenolfia appendiculata (50.0) and Polypodiodes amoena (50.0); (4) The species with the largest relative abundance is Tricholepidium maculosum (5.2); (5) Great morphological diversity and variations in size of pteridophytes; (6) The taxa are relatively complete and diversified in phylogeny; (7) The geographical elements are complexity and outstanded by mountainous endemic species of Tonkin Gulf of SE. Yunnan; (8) Ecological diver-sity.

Key words: Pteridophytes