Combined with the fundamental theorems of thermodynamics and the heat radiation theory, Pennes bioheat equation is improved, which can describe the thermal process in tissue subject to heat stimulation of moxibustion more vividly. Applying the Green function method, we derive the analytical solution of the equation and establish a straightforward way to quantitatively interpret the temperature behavior of living tissues, such as healthy tissue, tumor tissue, non-acupoint tissue and acupoint tissue, as a result of moxibustion. The concept of temperature attenuation coefficient (TAC) is proposed to measure the energy absorption at different depth of tissue. The coherence between the simulation and experiment about surface temperature demonstrates the flexibility and availability of the solution. The oscillation energy flow has a mild stimulus to the biological tissues, which is an advantageous physical exciter for organization to achieve its good functions. Our results reveal that the heat with high frequency is mainly absorbed by the surface layer, while that of low frequency can deeply penetrate into the living biological parts. Significantly, the diseases can be treated by moxibustion heat through the role of deep penetration.