An array substrate for a transflective liquid crystal display device is disclosed. The array substrate includes a substrate; a plurality of scanning lines and data lines on the substrate, crossing each other to define a plurality of pixel regions; a transmissive electrode disposed in the transmission region; and a reflector disposed in the reflection region and not subjected to a voltage. A lateral field is generated in the reflection region. The transflective LCD of the present invention achieves the maximum light efficiency in both reflection and transmission modes.