In this research, we study the fluctuation in the scattering probability of an electron in a nonlinear one-dimensional lattice system. A simulation of atomic vibration is performed and the fluctuation in the electron scattering probability by acoustic phonons is investigated. It is found that the fluctuation in the electron scattering probability of the equilibrium phonon mode state shows a 1/f(alpha) spectrum in the low-frequency range, provided that the temperature of the system is sufficiently high. Furthermore, the dependence of the number of atoms constituting the system is investigated. The 1/f(alpha) spectrum is more easily observed in a larger system than in a smaller one.