The present invention provides a driving circuit of pixel unit and a driving method thereof, and a display device. The driving circuit of pixel unit is configured to drive sub-pixel units on a display panel, and comprises a driving power supply signal port connected to the sub-pixel units through power supply signal lines and at least one compensation unit. The driving power supply signal port is configured to transfer a driving voltage output from the driving power supply to each of the sub-pixel units through the power supply signal lines. The compensation unit is configured to perform real-time compensation on voltage drops on the power supply signal lines when the sub-pixel units display different gray levels.