A substrate for light-emitting diode, a backlight module and a display device are disclosed. The substrate for light-emitting diode includes a plurality of light-emitting sub-regions, and each of the plurality of light-emitting sub-regions includes at least two anode electrode pads electrically connected through a first parallel-connection line, and at least two cathode electrode pads electrically connected through a second parallel-connection line. The at least two cathode electrode pads are disposed in one-to-one correspondence with the at least two anode electrode pads. At least one series-connection electrode pad group is further disposed between the anode electrode pad and the cathode electrode pad which are corresponding to each other; and each of the at least one series-connection electrode pad group includes two series electrode pads which are electrically connected through a series-connection line.