Embodiments of the present disclosure provide an OLED display panel and a driving method thereof. The OLED display panel includes a plurality of power lines, each power line connecting to a plurality of pixels, and one end of each power line connecting to a power source. The method includes acquiring a current value of the power line and comparing it to a preset threshold, when a current value of the power line is less than or equal to the threshold, providing an original data voltage to the pixels connected to the power line, when a current value of a power line is greater than the threshold, providing a compensating data voltage to the pixel connected to the power line. The compensating data voltage is equal to the difference between the original data voltage and the compensation voltage.