The study aimed to investigate the inhibition activity of the chemical compounds isolated from lichen Parmotrema tinctorum (Nyl.) Hale on the growth of Colletotrichum sp., Fusarium oxysporum and Pyricularia oryzae. The results showed that methyl haematommate, methyl β-orsellinate and methyl divaricatinate exhibited good antifungal activity. At the concentration of 700 μg/mL, methyl haematommate completely inhibited the growth of all fungi, while methyl β-orsellinate and methyl divaricatinate showed the complete inhibition of the fungal growth at lower concentrations between 100 and 200 μg/mL (except for F. oxysporum). In addition, the isolated compounds were also tested against the development of anthracnose caused by Colletotrichum sp. on chilli fruits (Capsicum hustler) in laboratory. Methyl β-orsellinate and methyl divaricatinate delayed the development of anthracnose to 12 days after infection, while the disease appeared on chilli fruits under the treatment of methyl haematommate within 8 days after infection. Current research results showed the potential of applying lichen compounds for prevention and treatment of fungal diseases in plants.