Charge-discharge properties of an La-modified Pb(Zr,Sn,Ti)O(3) (PLZST) antiferroelectric (AFE) ceramics capacitor were investigated by directly measuring its hysteresis loops and pulse discharge current-time curves under different electric fields. Large increments in polarization and discharge current were observed when the electric field increases from 3 to 3.5 kV/mm. Under 4 kV/mm, the first current peak of this AFE ceramics capacitor (static capacitance around 4.4 nF) can surpass 1.1 kA, and more than 80% electric charge stored can be released in < 65 ns. Moreover, this AFE ceramics capacitor can withstand 2000 times of charge-discharge cycling with no significant degradation of properties under 3.5 kV/mm.