  The pre-neutron-emission mass distributions for reaction $^{238}$U(n, f) up
to 60 MeV are systematically studied with an empirical fission potential model.
The energy dependence of the peaks and valleys of the pre-neutron-emission mass
distributions is described by an exponential form based on the newly measured
data. The energy dependence of evaporation neutrons before scission is also
considered, which plays a crucial role for the reasonable description of the
mass distributions. The measured data for the pre-neutron-emission mass
distributions for reaction $^{238}$U(n, f) are reasonably well reproduced up to
60 MeV. The mass distributions at unmeasured energies are also predicted with
this approach.
