We demonstrated a high performance flexible multi-barrier containing a silica nanoparticle-embedded organic–inorganic hybrid (S–H) nanocomposite and Al₂O₃. The multi-barrier was prepared by low-temperature Al₂O₃ atomic layer deposition and with a spin-coated S–H nanocomposite. The moisture barrier properties were investigated with a water vapor transmission rate (WVTR), estimated by a Ca test at 30°C, 90% R.H.. Moisture diffusion was effectively suppressed by the sub-700nm thick multi-barrier incorporating well-dispersed silica nanoparticles in the organic layer. A low WVTR of 1.14×10⁻⁵g/m²day and average transmittance of 85.8% in the visible region were obtained for the multi-barrier. After bending under tensile stress mode, the moisture barrier property of the multi-barriers was retained. The multi-barrier was successfully applied to thin-film encapsulation of OLEDs. The thin-film encapsulated OLEDs showed practicable current–voltage–luminance (I–V–L) characteristics and stable real operation over 700h under ambient conditions.