A transparent PLA/EVOH blend with maintained water vapor barrier property by reactive compatibilization was prepared. The improved compatibility contributed to much smaller particle sizes and more uniform size distribution of the EVOH dispersed domains than those of the EP and EPA samples. The reduction in light scattering caused by large particles significantly enhanced the transparency of the blend. Light transmission increased from 9.3% for the EPA sample to 83.5% for the EPAZn sample at 700 nm wavelength. The WVP values of the compatibilized blends remained the same as those of the incompatibilized blends. Comparing with PLA, the excellent transparency and improved water vapor barrier property of compatibilized PLA/EVOH blend widens its application range in packaging industry