The energy deposition process of electrical wire explosion under vacuum or low gas pressure circumstances is usually terminated prematurely, owing to the flashover along the surfaces of wires. Therefore energy deposited into wires can be far less than the amount needed to fully vaporize them. In this paper, a parallel connection method of wire is introduced in order to improve the energy deposition of the concerned wire before flashover takes place. Wire explosion driven by a current with a rise time of tens of ns and an amplitude of about 1 kA is studied numerically, and the simulation results show that by connecting a wire of a certain size in parallel with both ends of the exploding wire, the voltage rising rate is suppressed and the flashover is delayed; therefore the energy deposited into the concerned wire is increased effectively.