The invention provides an extraction method of a skin area in a medical image. The extraction method comprises the following steps of: importing the medical image of a patient, obtaining a sequence slice image; carrying out binary processing on the sequence slice image; carrying out high gray value point searching on the sequence binary slice image, and when a high gray value point is searched, judging whether the high gray value point is and isolated point, if yes, continuing searching, if not, carrying out contour tracking with the high gray value point serving as a start point, obtaining the number of contour point sets, then judging whether the number of contour point sets is larger than a preset threshold, if yes, indicating that skin area contour extraction is successful, if not, continuing searching for the next high gray value point until the number of obtained contour point sets is larger than the preset threshold, and obtaining a sequence skin contour image; carrying out area filling on the sequence skin contour image; and carrying out face extraction on the sequence skin contour image, obtaining three-dimensional face data of the skin area, and completing the extraction of the skin area. The method is simple to realize, high in speed and capable of meeting a plurality of clinic demands.