In this paper, the multi-photon spectrum of transmitted light for the mixed absorptive-dispersive optical system in good cavity case is discussed. Owing to the influence of detuning θ and △, not all the various peak values of the spectrum appear at the point of ω = ω0, and the coefficient of different peak value is not the same. Therefore, the spectrum of transmitted light will show various characters, such as single peak, multi-peaks or asymmetric ones.