The transmission of the pulses in the intracavity of the self-mode-locded Cr4 + ∶YAGlaser is analyzed theoretically.The initial starting and the condition of steady self-mode-locked pulses in the self-mode-locked Cr4 + ∶YAGlaser are discussed . This conclusion is consistent with the experiment of the self-mode-locked Cr4 + ∶YAGlaser.