An application of a phthalide compound in preparing a medicament. The medicament is specially used for promoting a stem cell to secrete one of the following items: telomerase, a neurotrophic factor (brain-derived neurotrophic factor, BDNF), a stem cell chemotactic factor (stromal cell-derived factor-1, SDF1), a stem cell chemotactic factor receptor (CXC chemokine receptor 4, CXCR4), and an immunoregulatory factor; a kit comprising a phthalide compound and a stem cell is also provided.