To study the matching relation between the exploding foil bridge size and the barrel, the ignition tests and the up-down experiments have been done. Results show that a preferred matching relation between inner diameter and bridge size was obtained. The up and down experiments of 0.3mm×0.3mm exploding foils matching with Φ0.45mm barrels were carried out. Results show that the threshold electrical current is almost lowered 300A. Accordingly, when small scale exploding foil and the barrel are prefer-ably matched, the threshold voltage of slapper detonators can be lowered.