One new aromatic compound ethyl cristiferoate (1), together with two depsides (2, 4), one depsidone (3), and two monoaromatic compounds (5, 6) were isolated from Parmotrema cristiferum (Taylor) Hale. The chemical structure of new compound was confirmed by analyses of NMR spectroscopy (1D and 2D) and high resolution mass spectroscopy. The structures of the others were interpreted based on NMR, MS as well as compared with the references. Some isolated compounds were tested for their α‐glucosidase inhibition and compounds 2 and 4 displayed remarkable inhibitory activities with IC50 around 10 µg/mL.