Three images of a coin are obtained by use of dielectric barrier discharge photography(DBDP) with the nanosecond pulse width of 4.7 ns,7.6 ns and 10.6 ns respectively.The result shows that with the increase of pulse width,the image contrast decreases.Based on the mechanism of DBDP,it is analyzed that after power is applied to the coin,the time lag of the discharge current pulse has a close relationship to the discharge gap.Then,the influence of nanosecond pulse width on the contrast of dielectric barrier discharge image is explained reasonably by the time lag.