Breakdown characteristics of the low-frequency dielectric barrier discharge (DBD) at low pressure are investigated experimentally in He,Ne and Ar.The current waveform of this DBD is a series of pulses that is caused by the results of the electron avalanches under the action of the applied field and the quenching effect of the wall-charges field on the avalanches.The experimental investigation and the theoretical analysis on its breakdown characteristics indicate that its breakdown voltage is higher then that calculated by Paschen law and depends respectively on the filled-gas pressure and the distance between the electrodes,instead of their product,due to considering the diffusion loss of the charged particles in the breakdown processes.The ion-induced secondary electron emission coefficient and the mean electron energy at the breakdown moment can also be determined approximately by measuring the breakdown characteristics of the discharge tubes with different distance between the electrodes.The experimental results and the theoretical analysis of this DBD are discussed in this paper.