Four species of Porpidia are newly reported from China, including one species new to science (Porpidia crystallina) and three records (Porpidia umbonifera, P. seakensis and P. cf. contraponenda) new to China. Porpidia crystallina is characterized by a macrocarpa-type exciple containing crystals, a Cinereorufa-green epihymenium, large ascospores and a lack of secondary metabolites. Morpho-anatomical, chemical and phylogenetic analyses were carried out to elucidate the placement of the species and to support the delimitation of the new taxon. Detailed taxonomic descriptions, ecological and chemical characters, and illustrations are provided for each species. A key to all known Chinese Porpidia species is also provided. ITS, Lecideaceae, lichens, phylogeny, taxonomy