Quantum properties of a two photon Jaynes-Cummings model (JCM) interacting with a single mode coherent light field is calculated mechanically without rotating wave approximation. The evolution properties of the two-photon JCM and JCM quantum entanglement and the atomic population inversion are contrasted. The effects of the mean photon number, the atom- field coupling coefficient and the detuning on the quantum entanglement and the atomic population inversion are studied. The numerical results indicate that, with the increase of the atom-field coupling coefficient, the period of the entanglement evolution disappear gradually, and it takes longer time for the mean entanglement to reach the maximum value with increasing of the mean photon number. The little indentation oscillation appears in the evolution curves of quantum entanglement and the collapse regime of the atomic population inversion, which is caused by virtual photon effect, weather increasing of the atom-field coupling coefficient or the mean photon number and the detuning.