Experiments of charging particles by short-pulse discharges were carried out under different voltages and the charge number on drops was measured by Millikan cell with and without a diversion cylinder. The results show that without the diversion cylinder, the charge number on drops increases with the increase of the voltage, while both the short-pulse voltages are lower than the broken-down voltage. The charge number on drops reaches the maximum when the short-pulse voltage is equal to the broken-down voltage. But when the short-pulse voltage is higher than broken-down voltage, the charge number on drops is decreased. However, when the diversion cylinder is present, the neutralization phenomenon could be avoided in the plasma region. The charge number on drops is higher than that in case without the diversion cylinder. But it is not beneficial to charging to use the diversion cylinder when the applied voltages are lower than the broken-down voltage. At the same time, the influence of the cylinder diameter on the charging on drops is studied and it is indicated that it is the best for charging of the short-pulse discharge when the diameter of the diversion cylinder is 2cm.