The preset disclosure relates to a pixel driving circuit, a pixel driving method, an array substrate and a display device. The pixel driving circuit includes a pixel driving unit and an optical detection unit. The pixel driving unit is configured to drive a light-emitting element included in a pixel unit to emit light. The optical detection unit includes a photoelectric conversion sub-circuit and a switch control sub-circuit. The photoelectric conversion sub-circuit is configured to receive light emitted from the light-emitting element, and convert the light into an electrical signal. The switch control sub-circuit is configured to output the electrical signal under control of a first scanning signal. The pixel driving unit is configured to adjust brightness of the light emitted from the light-emitting element according to the electrical signal.