Continuous wave laser radiation is used to heat up tumor tissue where the cells in this tissue are more sensitive to heating. Temperature distribution is connected to hyper thermal therapy. First, the nonlinear bio-heat transfer equation of Penne’s type in three dimensions was solved using the approximate analytical Adomian Decomposition Method (ADM), where the thermal conductivity of tissue and blood perfusion are temperature dependent. Next, this model was applied to study the effect of parameters such as laser powerand irradiated time, and impact of the parameters on laser heat distribution within the tumor tissue. It was found out that, the temperature of the tissue increases with laser powerand irradiation time. Finally, important effects in the simulation on laser thermal therapy are discussed.