The semiclassical rescattering model and the quantum-mechanical S matrix model are used to study the non-sequential double ionization of atoms and molecules in strong laser fields.Based on these two models, we can calculate ionization rate with different laser intensities, recoil ions momentum distribution and two-electron energy distribution. The numerical simulation results show that the semiclassical rescattering model coincides with the quantum-mechanical S matrix model when non-sequential double ionization of atoms and molecules is researched in strong laser fields.