Refined calculation of parameters during electroporation（EP） plays a key role in the treatment planning of EP. Based on five-layer dielectric model of a spherical cell

in consideration of step model of dielectric parameters and Smoluchowski EP equation

we investigated spatial and temporal distribution of EP parameters under the conditions of nanosecond pulsed electric field of 100 ns and 45 kV/cm. The results show that

compared to the simulation results of step model and EP equation with single EP equation

the permittivity near anode reaches twice of its initial value

changes in conductivity near anode will delay for 10 ns

and the transmembrane potential（TMP） will delay for 30 ns; the pore density near anode will decrease from 1012 m-2 to 109 m-2 at 50 ns; the pore density of plasma membrane 4～10 μm from anode will remain an initial value and local minimum value in TMP occurred 4～5 μm from anode. Therefore

the appearance and development of EP will delay in time

and the EP area along plasma membrane will significantly reduce in consideration of permittivity.