The interaction between a coherent state light field with time-varying frequency and two-level atoms is investigated under non-rotating-wave approximation. The time evolution of the atomic population inversion is discussed when the field frequency changes with time in a sine or a square wave way. The numerical results indicate that, when the light field frequency does not change with time, the period of atomic population inversion increases with the increase of the mean photon number. When the field frequency changes with time in a sine wave way, the collapse-revival period and the amplitude of atomic population inversion are strongly affected, and the frequency of the light field plays a modulation role in the oscillation frequency of evolution curves. When the field frequency changes with time in a square wave way, the collapse-revival period of the atomic population inversion changes and a new collapse-revival phenomenon emerges.