Hitherto only 24 species belonging to 11 families of spiders were reported from Mt. Seol-ak, the largest and highest mountain is located in the northern side of the Taebaeg range in Korea The authors investigated spider fauna of Mt. Seol-ak, through out the west and east, during 24, July-2, August 1979. In addition to this, material collected by Paik, N.K.(1972), Lee, H.S. (1973-1974), Jung, C.G. and Namkung (1976) were examined. 1) In this report, on 188 species of 101 genera, including 2 undetermined species, belonging to 25 families of spiders, are tabulated through the aid of published data and collection by the authors. 2) 164 species are added to the fauna, of which 7 species are unreported in Korea as follows: Enoplognatha margarita Yaginuma, 1964, Gonatium arimaense Oi, 1960, Araneus variegatus Yaginuma, 1960, Arctosa ebicha Yaginuma, 1960, Xerolycosa nemoralis(Westring, 1861), Synagelides agoriformis Strand, 1906, Kishidaia albimaculata(Saito, 1934), 3) The spider fauna of Mt. Seol-ak, include 35 northern species(18.8%), 5 southern species(2.7%), 6 cosmopolitan species(3.2%) and 140 palaearictic temperate species(74.5%), 4) The common species to comparative area and foreign countries as follows: Mt. Seol-ak-Jiri-san 102 species (44.9%), Mt. Seol-ak-Hanla-san 114 species (40.3%), Mt. Seol-ak-Japan 155 species (16.2%), Mt. Seol-ak-main China 62 species (6.9%), 5) The vertical distribution is as follows: 1500-1700m : 28 species (14.9%), 1200-1500m : 57 species (30.3%), 800-1200m : 103 species (54.8%), 500-800m : 107 species (56.9%), up to 500m : 123 species (65.4%) This figure indicated clearly that the higher altitudes, the fewer species are found, in localities above 1200m there were only 69 species. 6) The predominant species of Mt. Seol-ak are Araneids. Thomisids, Theridids, Linyphiids; Neriene emphana are found in large numbers between 600m and 1700m. Salticids and Lycosids are relatively few in number. 7) 48 species are common to in Korean cave spiders, especialy 6 species of troglophilous as follows: Nesticus coreanus Paik et Namkung, 1969, Mengea coreana Paik et Yaginuma, 1969, Meta menardi (Latreille, 1804), Coelotes coreanus Paik et Yaginuma, 1969, Coelotes songminjae Paik et Yaginuma, 1969, Cybaeus mosanensis Paik et Namkung, 1969.