It is a key component about wires in aircraft power system to transmit power and information. In the current context of energy conservation, emission reduction, and environmental protection, although copper wire has good conductivity and strong mechanical properties, due to its high density, copper wire is not very suitable for occasions that are very sensitive to weight requirements. In order to reduce aircraft weight and improve fuel efficiency, it has become a trend to use aluminum instead of copper wire. This paper introduces the basic principles of current aircraft wire selection, and then uses COMSOL Multiphysics simulation software, to compare and analyze the electrical, thermal and structural properties of aluminum and copper wires. The performance characteristics of two different materials were analyzed, and the performance advantages and application limitations of aluminum wires were summarized, aiming to optimize the design scheme of aircraft wires .The simulation results show that the good conductivity, thermal stability and mechanical strength of aluminum conductors can meet the requirements of some aircraft power systems.