Chemotherapy is a well-established method for treating cancer, but it has limited effectiveness due to its high dosage and harmful side effects. To address this issue, researchers have explored the use of photothermal agent nanoparticles as carriers for precise drug release in vivo. In this study, three different sizes of polydopamine nanoparticles (PDA–1, PDA–2, and PDA–3) were synthesized and evaluated. PDA–2 was selected for its optimal size, encapsulation rate, and drug loading rate. The release of the drug from PDA–2@TAX was tested at different pH and NIR laser irradiation levels. The results showed that PDA–2@TAX released more readily in an acidic environment and exhibited a high photothermal conversion efficiency when exposed to an 808 nm laser. In vitro experiments on ovarian cancer cells demonstrated that PDA–2@TAX effectively inhibited cell proliferation, highlighting its potential for synergistic chemotherapy-photothermal treatment.