An array substrate, a method for manufacturing the same and a liquid crystal display device are provided. A metal oxide semiconductor layer and an etching stop layer are sequentially formed on a gate insulating layer. One patterning process is performed in the etching stop layer to form a source electrode contact region via hole, a drain electrode contact region via hole and an insulation region. A source-drain electrode layer is formed on the etching stop layer. During a process of performing one patterning process in the source-drain electrode layer to form a source-drain electrode pattern, a portion of the metal oxide semiconductor layer corresponding to the insulation region is removed so that the metal oxide semiconductor layer is disconnected at a position corresponding to the insulation region. The insulation region surrounds the source-drain electrode pattern.