The invention discloses a spinning cake oil stain segmentation algorithm. The algorithm is used for detecting oil stain defects on the surface of a spinning cake on a chemical fiber production line. The algorithm comprises the following steps: carrying out graying processing on an acquired spinning cake image; carrying out blocking processing on the spinning cake by utilizing an image blocking algorithm so as to improve the algorithm execution speed; a homomorphic filter is used for carrying out illumination non-uniform elimination treatment on the spinning cake; performing filtering processing on the spinning cake image by using a filtering algorithm to remove excess noise; carrying out threshold segmentation on the filtered image so as to position an approximate area of oil stain; extracting a certain position of the left upper region of the oil stain as a seed point, and segmenting by a region growing method; carrying out morphological treatment on the segmented spinning cake imageto remove redundant holes and noise. The spinning cake greasy dirt segmentation algorithm can effectively segment surface greasy dirt on the spinning cake, has the advantage of high segmentation precision, can be applied to an actual spinning cake production line, and has a wide application prospect.