A comprehensive analysis for guided wave preferred fundamental excitation that satisfies cumulative conditions of second harmonic generation in a weakly nonlinear plate has been carried out and then confirmed by finite element modeling for selected cases. The properties of nonlinear forcing terms and secondary mode shapes are manipulated to determine the cumulative second harmonics. Analysis shows that the synchronism points with higher power flux intensity are the preferred fundamental excitations that are suitable for nonlinear guided wave NDE. Finite element modeling of SH mode and Lamb mode fundamental excitation has been conducted on the excitation points selected by the co-Analysis method. A linear increase of qualitative nonlinear parameter over the propagation distance has been observed for both Lamb wave and SH wave fundamental excitations.