Extraction method for region of interest of breast three-dimension image

The invention discloses an extraction method for a region of interest (ROI) of a breast three-dimension image. The method includes: performing denoising processing on the breast three-dimension image, dividing the breast three-dimension image into k cross sections in a Z-axis direction and selecting a two-dimension image I on the cross sections; through the grey information of the two-dimension image, respectively determining internal boundaries and external boundaries of the ROI in an X-axis direction and external boundaries of the ROI in a Y-axis direction; and selecting a two-dimension image I on a breast sagittal plane and respectively determining boundaries of the ROI in the Z-axis direction through the two-dimension image I. The extraction method for the ROI of the breast three-dimension image combines with the grey characteristic of the breast three-dimension image so that full-automatic extraction of the ROI is realized accurately and effectively.