E.coli ATCC25922 was treated by a laboratory scale continuous PEF system.Results showed that increase in inactivation ratio with the increase of applied electric field strength(5～30 kV/cm)and treatment time(133～266ms) and ultimately a stable value,which can result in 7.9 log cycle E.coli lethal rate.Single factor tests and Response Surface Method(RSM) analysis results demonstrated that factors of both electric field strength and treatment time affect E.coli lethal rate significantly(P<0.01),and electric filed strength has a more significant impact on sterilization effect.Accordingly,the optimum inactivation conditions acquired was electric field strength 35.6kV/cm and treatment time 256.1ms,which result in 8.3 log cycle E.coli lethal rate.