The evolution of the photonemigsion-spectra from a laser dressed atom is Investigated theoretically. The processes preparing initiative state and the effect of the initiative state on the exciting and spontaneous processes are discussed. The compasison of quantum theory and semiclassical theory for this study is made, when the drive field is coherent state, they are equivalent. The feature of the photonemission-spectra, its evonlation and some physical problems related to them are also discussed.