The importance of lightning strike damage tolerance is growing as metal components are increasingly being replaced with composite materials that provide light weight and high structural strength. However, the lightning strike damage evaluation methods used in laboratories are prone to misinterpretation due to the lack of specific assessment guidelines in the standards. Previously, we have shown that lightning strike damage could appear to be more or less severe depending on the size of discharge electrode and the configuration of ground electrode. In this study, we numerically show the effect of testbed configuration on the temperature of lightning arc channel and test samples assuming continuous discharge current. We use COMSOL Multiphysics, a Finite Element Analysis (FEA) tool, for the modeling of lightning arc discharge. The results of the simulation are compared with the experimental results to fundamentally understand the impact of lightning channel diameter and ground electrode configuration on the lightning strike damage evaluation of the composite samples. The results of this study aid in the development of standards for lightning strike damage evaluation.