A survey of ectomycorrhizal fungi was performed during 2009–2011 and 2015 in Byeonsanbando National Park. A total of 3,624 individuals were collected, which belonged one division, 1 class, 5 orders, 13 families, 33 genera, 131 species. The majority of the fruiting bodies belonged to orders Agaricales, Russulales, and Boletales, whereas a minority belonged to orders Cantharellales and Thelephorale. In Agaricales, there were 6 families, 9 genera, 49 species, and 1,343 individuals; in Russulales, 1 family, 2 genera, 35 species, and 854 individuals; in Boletales, 4 families, 19 genera, 40 species, and 805 individuals; in Cantharellales, 1 family, 2 genera, 5 species, and 609 individuals; and in Thelephorale, 1 family, 1 genus, 2 species, and 13 individuals. The most frequently observed families were Russulaceae (854 individuals representing 35 species), Boletaceae (652 individuals representing 34 species), and Amanitaceae (754 individuals representing 25 species). The greatest numbers of overall and dominant species and individual fruiting bodies were observed in July. Most species and individuals were observed at altitudes of 1~99 m, and population sizes dropped significantly at altitudes of 300 m and higher. Apparently, the highest diversity of species and individuals occurred at climatic conditions with a mean temperature of 23.0~25.9 oC, maximum temperature of 28.0~29.9 oC, minimum temperature of 21.0~22.9 oC, relative humidity of 77.0~79.9%, and rainfall of 300 mm or more.