A regulating method and a regulating apparatus for a driving voltage of a display module, wherein the method comprises: applying, to the display module, a gamma voltage pair corresponding to a grayscale to be tested, selecting a test image and maintaining the test image for a predetermined time duration (11); switching to a predetermined grayscale image that matches the grayscale to be tested, regulating a common voltage of the display module, and recording a direction and a magnitude of regulation of the common voltage (12); and restoring the common voltage to a magnitude before the regulation, and regulating the first gamma voltage and the second gamma voltage according to the recorded direction and magnitude of regulation of the common voltage (13). Regulation accuracy of the driving voltage can be improved, workload for debugging can be reduced and work efficiency can be improved.