A total of 1,465 individuals from 58 species of wild orchids were found ranging from 72 to 696 orchids per trail. The number of orchid species was ranging from 7 to 30 species per trail. Sanyen nature trail had the highest number of wild orchid species, abundance and biodiversity index. Thirty wild orchid species of 697 individuals found in this trail provided the Shannon-Weiner index of 4.462. Various habitats of orchid in Khao Nan National Park were found. The specimens were classified into three groups: epiphyte, terrestrial plant and lithophyte. There were 35 epiphytic species belonging to 22 genera, 14 terrestrial species belonging to 13 genera and 2 lithophyte species belonging to 2 genera. This indicates that most of orchids at Khao Nan National Park were epiphytes.