The influence of the potential barrier in the organic-inorganic hybrid luminescent devices(SiO2/PPV) on photoelectric properties is studied.For ITO/PPV/Al and ITO/PPV/SiO2/Al,the injection of the holes lies on the potential barrier on the interface of ITO/PPV.The holes are the majority carriers,so the intensity of the luminescence lies on the amount of the injected electrons.The ability of the injection of electrons in the single layer device is dependent on the potential barrier on the PPV/Al interface.The improvements of luminescence intensity and efficiency in double layer devices are due to the SiO2 layer which makes the ability of electron injection stronger.For the three-layer device ITO/SiO2/PPV/SiO2/Al,the potential barriers in two injection directions are different,and the abilities of the electron injection are different.The maximum of the instantaneous luminescence intensity,when the ITO is under positive voltage,is 1.3 times of that when the ITO contact is under negative voltage.