The invention discloses novel application of a lanosterol triterpenoid compound as an anticancer medicament adjuvant, and the lanosterol triterpenoid compound is separated from Ganoderma colossum. In-vitro experiments confirm that the lanosterol triterpenoid compound has the efficacy of promoting anticancer medicaments to kill cancer cells, and especially is capable of promoting anticancer medicaments to generate cytotoxicity in non-small cell lung cancer cells with resistance to Iressa and liver cancer cells with resistance to Sorafenib.