We derive a set of equations characterizing the quantum statistical properties of Jaynes-Cummings model, which may be used to describe overall the dynamical and statistical aspects in the interaction between a two-level atom and a single mode of the radiation field. Both interactions of a two-level atom with a vacuum field and a excited atom with a coherent field, as examples, are discussed in detail. Finally, the practicality of the above-mentionedi theoretical studies is demonstrated.