Triple negative breast cancer (TNBC) represents a highly aggressive variant of breast cancer characterized by elevated rates of recurrence and mortality. Chemotherapy's application as a main cancer therapy is restricted due to its harmful side effects and resistance to medication. In this study, we utilized a covalent organic framework (COF) to apply indocyanine green (ICG), a photothermal agent, and gambogic acid (GA), an inhibitor of heat shock protein 90 (HSP90), to treat triple negative breast cancer. MTT results showed that the viability of tumor cells decreased more under laser irradiation conditions after the addition of GA than in the COF@ICG group. In addition, protein blotting results showed that under the action of GA, the blank group exhibited significantly higher HSP90 expression levels than the experimental group. The above results indicate that COF@ICG@GA enhances the therapeutic effect of PTT on cancer by inhibiting the expression of HSP90 in triple negative breast cancer cells and enhancing the sensitivity of tumor cells to temperature.