Based on the linear instability theory, the dispersion equation of charged liquid jet was obtained. The charged liquid jet breakup length was measured by applying the high-speed photography technology to verify the theoretical results. The results of numerical calculation indicated that the growth rate of 0-order and 1-order surface wave grows with increasing of jet velocity and charged voltage. The maximum growth rate of 0-order surface wave was bigger than that of 1-order surface wave in the discussed range of jet velocity and charge voltage. The jet breakup length increased to maximum value and then decreased with increasing of jet velocity. Charge voltage always promoted the jet breakup and makes jet breakup length shorter. Higher liquid conductivity made jet breakup length longer. The experimental results showed that theoretical analysis gave a reasonable explanation to the influence of charge voltage，jet velocity and liquid conductivity on jet breakup length, but fails to be a good predictor of critical jet velocity corresponding to the maximum of jet breakup length.