Abstract: The atomic population and quantum entanglement in the system of binomial light field interacting with v-type three-level atom are calculated exactly without rotating wave approximation. The influence of the binomial light field parameter on atomic population and quantum entanglement is studied, and the influence of the superposition of atomic energy levels at the initial time on the quantum entanglement is also discussed. The results show that the collapse-revival period of atomic population increases gradually with the increase of , and the collapse-revival region manifests chaotic characters when is big enough. In addition, with the increase of , the periodicity of quantum entanglement evolution gradually disappears, which is presented as when the atom is in the excited state at the initial time, the entanglement value at the initial stage and the evolution average value increase gradually，while when the atom is initially in the superposition state, the degree of entanglement decreases gradually. And it is also shown that in the non-rotating wave approximation, both of the atomic population probability and the evolution curve of the entanglement between the light field and atom show small sawtooth oscillation.

Key words: quantum optics, atomic population, quantum entanglement, non-rotating wave approximation, three-level atom