An array substrate and a manufacturing method thereof, a motherboard and a display device are disclosed. The array substrate has a display region and a non-display region, and includes a base substrate, and a plurality of signal lines and at least one transfer electrode that are on the base substrate. The plurality of signal lines extend from the display region to the non-display region along a first direction, at least one of the plurality of signal lines includes a first trace in the display region and a second trace in the non-display region, the second trace includes at least two sub-traces disconnected from each other, a sub-trace, close to the display region, of the at least two sub-traces of the second trace is directly connected with the first trace, and every two adjacent sub-traces of the second trace are electrically connected with each other.