[in Thai language with English abstract:] This study is to collect discolichens on bark and rocks in Phu Luang Wildlife Sanctuary, Loei province, during June 2008 to November 2009. The total of 342 specimens were collected from 4 forest types: lower montane scrub, tropical rainforest, lower montane rain forest and dry dipterocarp forest at the elevation 700-1,555 metres above sea levels. The samples were identified into 12 families 15 genera 40 species, among them four species: Bacidia spadicia, Haematomma africanum, H. infuscum and Lecanora allophana, were to be new record to Thailand. Twelve species: Acarospora PL. 1-J, Bacidia PL.1, Bacidia PL.1-J, Bacidia PL.2, Brigantiaea PL.1, Lecanora PL.1, Lecanora PL.1-J, Lecanora PL.2, Lecanora PL.2-J, Placynthiella PL.1, Ramboldia PL.1 and Ramboldia PL.1-J, were expected to be new species to science. The species diversity of discolichens in lower montane scrub, lower montane rain forest, tropical rainforest and dry dipterocarp forest were 72, 19, 7 and 2 percent, respectively. KEYWORDS: lichen, diversity, discolichens, Phu Luang Wildlife Sanctuary