Pixel circuit, driving method thereof, display panel and display device

The invention discloses a pixel circuit, a driving method thereof, a display panel and a display device. Power source signals used for driving a light emitting device to emit light may be the signals of a first power source signal end, and may be the signals of a second power source signal end; when a high-brightness image is required to be displayed, a selection module outputs the signals of the first power source signal end to a second node, and the power source signals for driving the light emitting device to emit light are the signals of the first power source signal end; when a low-brightness image is required to be displayed, the selection module inputs the signals of the second power source signal end to the second node, so that the power source signals used for driving the light emitting device to emit light are the signals of the second power source signal end; and therefore, under the condition that the display of the high-brightness image and the low-brightness image is realized, different power source signals are respectively adopted to drive the light emitting device to emit light, and thus, the improvement of the utilization rate of the power source signals can be improved, and the power consumption of the pixel circuit can be decreased, and the power consumption of the display panel can be reduced.