The disclosure is related to an array substrate, a display panel and a method for detecting the array substrate. The array substrate comprises a plurality of pixels arranged in an array. Each of the pixels comprises a plurality of sub-pixels arranged in sequence. Each of the sub-pixels is arranged opposite to a capacitor at an interval. Each sub-pixel comprises a sub-pixel electrode. At least one sub-pixel electrode comprises an extension portion. At least one extension portion of the sub-pixel electrode of the sub-pixel is arranged corresponding to the space between the adjacent sub-pixel and the capacitor corresponding to the adjacent sub-pixel.