To assess the penalty due to nonlinear effect in C+L band long-haul optical amplified transmission link, a new parameter of modified nonlinear phase shift (\phi_(D) is proposed, which is the accumulated nonlinear phase shift weighted by a normalized group velocity dispersion (GVD). Based on the numerical simulation result of broadband long-haul hybrid Raman/erbium-doped fiber amplified transmission line, it is validated that \phi_(D) is more reasonable and suitable than the previous proposed nonlinear phase shift (\phi_(NL) for broadband applications.