Composites are widely used in numerous industries, especially the aerospace industry. Although it has an overall high performance, it may present some disadvantages compared to metals regarding aircraft lightning strike protection. Thus, the present paper aims to evaluate the influence of the anisotropy characteristics related to carbon fiber reinforcement plastics (CFRP) over the effects of lightning strike on aircraft built with such material. This analysis is performed through a numerical simulation which is based on the finite difference time domain (FDTD) method, such method allows analyzing the electro-thermal coupling phenomenon related to this problem. The existent dependency between the physical properties related to this problem is taken into consideration in this work. In order to perform the proposed analysis both the electromagnetic and the thermal propagation in the composite material shall be verified. The physical properties and some important considerations regarding the lighting strike phenomenon on composite aircraft and its effects are presented.