Investigation of the leaves of Chloranthus tianmushanensis resulted in the isolation and characterization of two new sesquiterpene dimers with a rare 18-membered triester ring, tianmushanol (1) and 8-O-methyltianmushanol (2), and four known sesquiterpenes. Their structures were established by spectroscopic means. The inhibitory activities against tyrosinase of all isolates were also evaluated.