In this paper, we employ extended tanh-function method and the
(G'/G )-expansion method to find the exact traveling wave solutions
involving parameters of nonlinear evolution equation Modified Liouville
equation and comparison between this two method and another
method which have been solved it. When these parameters
are taken to be special values, the solitary wave solutions are derived
from the exact traveling wave solutions. It is shown that the
proposed methods provides a more powerful mathematical tool for
constructing exact traveling wave solutions for many other nonlinear
evolution equations.