Various nano-targeted drug delivery systems have been developed for combined photothermal–photodynamic (PTT–PDT) treatment of tumors due to better outcomes compared with monomodality therapy. Here, we constructed a facile two-step method without core templates to obtain indocyanine green (ICG) loaded-hyaluronic acid (HA) surface-coated polydopamine nanoparticles (IIPH). The prepared nanoparticles demonstrated an excellent photothermal conversion capacity and efficient singlet oxygen production. Both in vitro and in vivo studies proved that IIPH could significantly inhibit the growth of tumor by PTT–PDT combinational treatment. All the results indicated that IIPH NPs hold great potential to be utilized as a new photothermal–photodynamic composite for cancer treatment.