The interaction potential for deformed-spherical nuclear pair is derived microscopically in the framework of double folding model with M3Y-Paris nucleon–nucleon interaction. The heavy target nucleus 238 U together with the light projectile nucleus 16 O are considered as an example. The exchange part of the heavy ion (HI) potential has been calculated using finite-range exchange NN force instead of the zero-range pseudoforce. Neutron thickness and the difference in kinetic energy densities between neutrons and protons have been taken into consideration in calculating the exchange HI potential. For this pair the fusion cross-section as well as the barrier distribution are calculated. These calculations have been done using three different values of hexadecapole deformation parameter of 238 U . The effect of using both the finite-range exchange NN force and the hexadecapole deformation on the fusion cross-section and the barrier distribution have been discussed.