  In order to estimate qualitatively the influence of nonequilibrium evolution
in relativistic heavy ion collisions, we use the three dimensional Ising model
with Metropolis algorithm to study the evolution from nonequilibrium to
equilibrium on the phase boundary. The evolution of order parameter approaches
its equilibrium value exponentially, the same as that given by Langevin
equation. The average relaxation time is defined which is demonstrated to well
represent the relaxation time in dynamical equations. It is shown that the
average relaxation time at critical temperature diverges as the zth power of
system size. The third and the fourth cumulants of order parameter during the
nonequilibrium evolution could be either positive or negative, depending on the
observation time, consistent with dynamical models at T > Tc. It is found that
the nonequilibrium evolution at T > Tc lasts very short, and the influence is
weaker than that at T < Tc. Those qualitative features are instructive to
determine experimentally the critical point and the phase boundary of QCD.
