To the person who taught me patience, strife, and pushed me towards success in life and give me all care and happiness. Numerical method such as FDTD method has been used to study theoretically the biological effect of electromagnetic waves produces from Mobil phone base station on life tissues. The theory is presented for determining the biological effect of mobile phone base station on life tissues; It has been studied theoretically the propagation and absorption electromagnetic waves produced from mobile phone base station on life tissue. The model is a plane homogeneous slab of tissue under the irradiance of normal incidence plane wave. The layer consists of four tissues as skin, fat, muscles and organ. It has been discussed by obtaining the electromagnetic field, absorbent power, specific absorption rate in the model. Graphs have been plotted using software program as matlab