The present disclosure provides an array substrate, its manufacturing method and testing method, and a display device. The array substrate includes a (Test Element Group) TEG arranged at a non-display area and including a plurality of to-be-tested elements and a plurality of testing contact electrodes configured to test the to-be-tested elements. Each of the to-be-tested elements is connected to at least two of the testing contact electrodes, and at least one of the testing contact electrodes is shared by at least two of the to-be-tested elements.