Eu3+ doped Sr2CeO4 samples were prepared by a solid-state method and the luminescent properties of the samples with and without adsorbed moisture were investigated. When the Sr2-xEuxCeO4+x/2 samples were prepared, it was found that only the excitation energy in the strong charge-transfer-state (CTS) band of Ce4+—O2- peaking at about 35700cm-1 was transferred to Eu3+ion while that in the weak CTS band of Ce4+—O2- located at about 29400cm-1 led to Ce4+—O2- charge-transfer (CT) emission. After adsorption of moisture in the Sr2-xEuxCeO4+x/2 samples, the intensity of Eu3+intra-4f6 absorption transition increased remarkably, the energy transfer took place from the two Ce4+—O2- CTS bands to Eu3+ ion. The excitation energy in the strong Ce4+—O2- CTS band was transferred to the Eu3+—O2- CTS band through radiationless process involving exchange interaction, however, the weak Ce4+—O2- CTS band caused the excitation to the Eu3+ excited levels through resonance radiationless process by a multipole interaction mechanism.