Species diversity of ferns in Khlung district, Chanthaburi province was explored and collected specimen from December, 2015 to January, 2019. Forty species, 28 genera and 19 families can be identified. The 7 species of Polypodiaceae were found the most in the study sites. The habits can be divided into 4 types consisting of 22 terrestrial ferns, 12 species of epiphytic fern, 5 species of climbing fern and 1 species of aquatic fern. Angiopteris evecta (Forst.) Hoffm, Cibotium barometz (L.) J.Sm. and Platycerium coronarium (Mull.) Desv. were uncommon found in this local habitat. The highest number of species was found at Bo Walu sub-district while the lowest was found at Kwian Hak sub-district. Thus, the result can be used to planning for conservation of ferns resource in situ conservation.