The present invention provides a method of raising contrast of an OLED display panel and a system. The method converts the original RGB signal into a HSI color space constructed by a hue component, a saturation component and an intensity component, and implements histogram statistics to the intensity component to obtain a histogram of the intensity component, and obtains a conversion parameter according to the histogram of the intensity component, and obtains the new low driving voltage with calculation of the conversion parameter in combination with the original low driving voltage, and meanwhile, keeps the hue component and the saturation component unchanged, and implements enhancement treatment to the intensity component to obtain a new intensity component, and then, converts the hue component, the saturation component and the new intensity component into a RGB color space to obtain a new R′ G′ B′ signal, and provides the new R′ G′ B′ signal and the new low driving voltage to a pixel driving circuit. The method can raise the contrast of the OLED display panel, promote the display quality of the OLED display panel and reduce the power consumption of the OLED display panel.