Provided are a pixel circuit and driving method thereof, array substrate and display device. The pixel circuit includes a light-emitting element, a driving sub-circuit, a scanning sub-circuit, and a carrier releasing sub-circuit. The driving sub-circuit is connected to a first electrode of light-emitting element, and the driving sub-circuit is configured to store a driving voltage and control the magnitude of a current passing through light-emitting element according to the driving voltage; the scanning sub-circuit is connected to driving sub-circuit. The scanning sub-circuit is configured to update the driving voltage stored by driving sub-circuit during the effective period of first scanning signal; the carrier releasing sub-circuit is connected to a second electrode of light-emitting element, and provides a reverse bias voltage to the second electrode of light-emitting element during the effective period of second scanning signal, thereby delaying the decrease of light-emitting efficiency of light-emitting element along with the service time.