Abstract: A two-dimensional mathematical model to describe the dynamic photo-thermal interactions during laser-induced interstitial thermotherapy under temperature control was developed here. A modified Monte Carlo method was developed to simulate photon transport in the tissue with a non-uniform optical property field, the finite volume method was used to numerically solve the Pennes bioheat equation to calculate the temperature distribution and the Arrhenius equation was used to predict the thermal damage extent. The effects of different laser sources, laser power and temperature control range on the thermal damage volume were analyzed based on the present model. The numerical results showed that the sizes of the thermal damage zones can be optimized by selecting appropriate parameters.