In this thesis, four large classes of nonlinear wave equations are studied, and the existence of solitary wave, kink and anti- kink wave, and uncountably many periodic wave solutions is proved. The analysis is based on the bifurcation theory of dynamical systems. Under some parametric conditions, various sufficient conditions for the existence of the aforementioned wave solutions are derived. Moreover, all possible exact parametric representations of solitary wave, kink and anti- kink wave, and periodic wave solutions are obtained and classified. One of these equations to numerically simulated.