In the current work, inverse design of symmetric double pole piece magnetic lenses has been introduced by using a VDTML software mentioned before, mathematical function as target function which has been used for Clarify the axial magnetic field, A mathematical function containing physical and geometric coefficients of the magnetic lens is adopted. Electron beam path was calculated using the distribution of the axial magnetic field along the lens axis in a telescopic magnification pattern using the fourth order Runge-Kutta method. And that is by calculating the distribution of the axial magnetic field and its first derivative, the path of the electron beam and its first derivative, in order to calculate the objective focal characteristics. There is a possibility to find the optimal shape of the magnetic pole piece after calculating the numerical axial magnetic potential parallel to the axial magnetic field and its derivative of the first and second order

symmetric lens, pole piece lens, cardinal points, magnetic lenses.