The invention provides a leather area measuring system and a method based on a digital image method, which comprises a CCD video camera connected with an image acquisition device lens, the CCD video camera is connected with an image collection card and a computer; the measurement steps comprise: first, calibrating the system to gain the system pixel equivalent Epsilon, and the practical dimension represented by unit pixel, second, obtaining the gray image of the leather to be measured, third, denoising the gray image, fourth, converting the gray image to a binary image using an iterative threshold method, and separating the object from the background area, fifth, denoising the image for a second time, sixth, processing a leather image by a vector analysis method, and obtaining the edge outline and the pixel number of the object area, and seventh, calculating the leather area to be measured. The invention has the advantages of low cost, non-contact, high measuring precision, and convenient industrial use.