A display device and an array substrate are disclosed. The display device includes a display panel and signal boards which supply signals to the display panel. At least a pair of signal boards that are connected with each other is electrically connected using a plug-in connection mode. A first plug-in structure is provided on a first signal board of each pair of signal boards connected in the plug-in connection mode, and a second plug-in structure corresponding to the first plug-in structure is provided on a second signal board of the pair of signal boards connected in the plug-in connection mode. Because at least a pair of signal boards that are connected with each other is electrically connected using a plug-in connection mode, a quantity of signal lines arranged between signal boards is reduced, which enables assembly and disassembly be more convenient.