The invention provides a textile defect detection method based on a peak value coverage value and area calculating. The method is characterized by analyzing digital image pixel gray scale informationof a flat textile surface under an illumination light source; segmenting an image into grids which are not overlapped; calculating an area of each grid; and according to area distribution, automatically positioning a textile surface defect. The method is especially suitable for automatically identifying the textile surface defect in a textile flat surface gray scale digital image collected under astable illumination light source.