Thermal plasmonic nanoparticles offer a novel and significant approach for photothermal therapy in the medical field, which is photothermal therapy of cancer. This study introduces a type of core-shell nanorods with internal coupling of titanium nitride (TiN) and gold (Au) nanomaterials. The photothermal properties of these nanorods in the near infrared (NIR) band were investigated using COMSOL Multiphysics software and the finite element method. Results indicate that TiN@Au and Au@TiN core-shell nanorods exhibit superior photothermal properties in the NIR band compared to pure TiN nanorods of similar volume. Furthermore, core-shell nanorods with polarization angles of 0° and 45° demonstrate enhanced optical absorption properties in the near infrared range. Furthermore, the study on the tunability of localized surface plasmon resonance with variations in core diameter, shell thickness, and combined changes of core diameter and shell thickness for core-shell nanorods of equal volume suggests that TiN@Au core-shell nanorods with a 10 nm Au shell offer increased optical absorption efficiency and photothermal conversion capability. Ultimately, the TiN and Au core-shell nanorods proposed in this research offer valuable insights for the structural design and heat transfer control of nanoparticle heat generators to enhance fluid temperature, as well as provide practical guidance for the preparation of core-shell nanoparticles.