[in Thai language with English abstract:] The main objective of this investigation is to compile crustose lichen of Physciaceae at various places of Thailand for taxonomic identification, determination keys and taxonomic database construction. From 632 lichen collecting samples during January 2003 to January 2010 of corticolous and saxicolous from 11 provinces, nine forest types: mangrove forest, lower montane forest, lower montane rain forest, dry evergreen forest, lower montane scrub, dry dipterocarp forest, mixed deciduous forest, tropical evergreen rain forest and strand vegetation, were identified into four genera: Amandinea, Buellia, Dimelaena and Rinodina, totally 34 species. Amandinea diorista, Buellia almeriensis, B. chloroleuca, B. subsororioides, B. triseptata and Dimelaena weberi, were found to be new record to Thailand. There were four unknown taxa expecting to be new species, whereas the common crustose lichens were Buellia curtisii, B. erubescens and B. glaucotheca. KEYWORDS: Crustose lichens, saxicolous, corticolous, family Physciaceae