A display panel, a manufacturing method thereof and a display device are disclosed. The display panel includes: a display region including at least one rounded corner; and a non-display region located at a periphery of the display region. The non-display region includes: a gate drive circuit; and a plurality of first dummy pixels located outside the at least one rounded corner of the display region, a first power line of each of the plurality of the first dummy pixels being connected with a signal line of the gate drive circuit.