Targeting nanoparticles to the tumor site is a salient feature for the tumor ablation during plasmonic photo-thermal therapy. Many of the safety considerations in surgical intervention suggest the alternative route of laser irradiation for photo-thermal destruction of tissues in presence of gold nanorods. The degree of tissue damage depends on laser irradiation parameters such as power, and image size as well as absorption and scattering properties of tissues. This paper analyzes, using finite element modeling, photo-thermal heating of tumor in the presence of intravenous blood injection or intratumorally injected gold nanorods. The Pennes bio-heat transfer equation was solved to compute temperature evolution. A volumetric heat generation based on Beer-Lambert law was used to model the laser heating. The predicted temperatures at the tumor surface were compared with available experimental results and are found to be good. To determine the efficacy of intratumoral injection of nanoparticles, a comparative study was also carried out to investigate the tumor thermal history for both the blood injection and targeted injection. Thermal damage of the tumor tissue was predicted by virtue of denaturation of single protein. It was found that a significant protein denaturation occurs when the temperature reaches around 53° C. A parametric study using the numerical model was also performed to quantify the effects of size and depth of the tumor, laser power and the concentration of the nanoparticles. Following intratumoral targeted injection; the computational heat transport modeling can be used to predict photo-thermal heating during laser irradiation.