In the heat treatment process, blood perfusion starts up a negative feedback mechanism. The blood temperature undergoes a transient process before onset of equilibrium, and then changes the situation of temperature distribution. In substance, the blood temperature undergoes a transient process for heat exchange between blood and tissue. For more fully exploring the heat transfer behavior of biological tissue, this paper analyzes the bio-heat transfer problem with the non-constant blood temperature based on the Pennes bioheat equation. A numerical scheme based on the Laplace transform is proposed to solve the bio-heat transfer problem with simultaneous equations.