A display panel and a driving method thereof, a display device. The display panel includes a common cathode, a first power terminal, a first wire and a first switch. The driving method includes: obtaining a total image current of a display image; and determining whether the total image current is greater than a first threshold current, if the total image current is greater than the first threshold current, controlling the first switch to disconnect the first wire, if the total image current is not greater than the first threshold current, controlling the first switch to connect the first wire, so that the second side of the common cathode is connected to the first power terminal through the first wire.