Abstract: As a kind of new concept kinetic weapons in strong magnetic environment, electromagnetic railgun can accelerate macro projectiles to hypervelocity using the electromagnetic force. However, the current distribution in conductors of railguns is sharply uneven, which may affect the system efficiency or the launching reliability. In this paper, as for a kind of complex railguns with copper strips, according to proximity effect about current distribution in conductors, two iron sheathes were added to the sides of the copper strips. A model was proposed, and simulation on current distribution was performed. The simulation results showed that the current in the copper strip was much evenly distributed. All these results are significant to current-carrying capacity of conductors and railguns engineering development.