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.