The invention provides an image processing method based on an integral histogram. The method comprises the steps of: step S1: creating an integral histogram and step S2: calculating histograms at any rectangular area of an image by using the integral histogram. The invention also provides an image processing system based on the integral histogram, which comprises an integral histogram creating unit and a histogram calculating unit, wherein, the histogram calculating unit calculates the histograms at any rectangular area of the image according to the integral histogram created by the integral histogram creating unit. The method and the system can not only improve the speed in calculating the histogram, but also reduce the amount of calculation of the histogram. In addition, the horizontal slipping to the histogram can reduce the support domain border and the potential boundary effects caused by the interval quantization of the histogram, and enhance the stability of the calculation result of the histogram.