2D gel electrophoresis (2DGE) plays an important role in proteomics. It can separate proteins effectively with their pl values and molecular weights. Proteornics researchers needed to identify interested protein spots by examining the gel. This is time consuming and labor extensive. It is desired that the computer can analyze the proteins automatically by first detecting and quantifying the protein spots in the digitized 2DGE images. In our work, we will investigate the use of the watershed algorithm in segmenting the protein spots from the varying background. However, the watershed algorithm often produces an over-segmented result. So, we will introduce the notion of fuzzy relations to improve the segmentation result.