[in Chinese with English abstract:] The anti‐tumor activities of usnic acid, evernic acid, barbatic acid and salazinic acid extracted from thallus of Ramalina conduplicans were studied. The anti‐tumor rate, and thymus and spleen indexes were calculated and the content of serum IL‐2 were detected. The results showed that usnic acid [20mg/(kg∙d), 10mg/(kg∙d)], evernic acid [20mg/(kg∙d), 10mg/(kg∙d)], barbatic acid [5mg/(kg∙d)], and salazinic acid [20mg/(kg∙d)] had obviously inhibitory effect on the tumor in H22 mice. The anti‐tumor rate of these compounds were obviously higher than that of negative control (P<0.01). These four compounds can influence thymus and spleen indexes and the content of serum IL‐2 in treated H22 mice was significantly higher than that in negative and control (P<0.01). Key words: usnic acid, evernic acid, barbatic acid, salazinic acid, interlenkin‐2.