The electron emission of a novel antiferroelectric cathode material La-doped Pb(Zr，Sn，Ti)O3(PLZST)has been studied. For driving voltage of 800V and accelerating voltage of 0V，the emission current density was 1.27A/cm2. For driving voltage of 800V and accelerating voltage of 4kV，a strong emission current density with 1700A/cm2 was obtained. The dependence of emission current on accelerating voltage was analyzed and the mechanism of antiferroelectric electron emission was discussed. It was found that strong electron emission from antiferroelectric material can be realized under lower driving voltage and the emission current was much larger than that predicted by the Child-Langmuir law. Local antiferroelectric-ferroelectric phase transition in the vicinity of the triple junction leads to initial electron emission，and these initial electrons then cause desorption of gas which had been absorbed at the ceramic surface.The desorbed gas is then ionized，which leads to plasma generation. The formation of surface plasma enhances the emission current.