Embodiments of the present disclosure relate to a technical field of display technology, and provide a driving method for a pixel circuit and a driving device thereof. A problem of cost increase can be solved which is caused by an increase in a number of storages when adjustment is made by way of Gamma curve and table lookup, by means of the technical solutions according to embodiments of the present disclosure. The driving method of the pixel circuit includes acquiring brightness information of a display screen in a light-emitting phase (S101); determining a duty cycle of a pulse signal according to the brightness information (S102); inputting a high level to the first voltage terminal, and inputting the pulse signal with the duty cycle to a gate of the first switching transistor by the first gate line (S103).