Provided are a compensation method for a display panel and a display device. The compensation method for a display panel includes: obtaining a first display grayscale obtained to be displayed in a to-be-displayed image by a first sub-pixel, and obtaining a first display data voltage corresponding to the first display grayscale; determining whether the first display data voltage is greater than a low brightness demarcation voltage; and if yes, obtaining a first compensation data voltage corresponding to the first sub-pixel according to the first display grayscale; and determining, according to a lighting voltage corresponding to the first sub-pixel, whether the first compensation data voltage is in a dark-state voltage range; and if yes, compensating the first sub-pixel by using the lighting voltage corresponding to the first sub-pixel, and if not, compensating the first sub-pixel by using the first compensation data voltage.