The exactly analytic solution of the coherent sbate Jaynes-Cummings (JC) model is derived for the detunings using the interaction picture. The atomic level occupation probabilities are investig-ated numerically as function of time and detuning parameter and initial mean photon number. For detuning parameter, the quantum collapse and revival phenomenon of the atomic level occupation probabilities is found. Interference between revival signals is discussed. The time evolution of the coherent states of field is studied numerically. It is discovered that the evolution of the state of field appears to be quasi-reversible for a short period of time. This is an interesting and important new phenomenon of JC model. Detailed discussion is presented.