To overcome the difficulty caused by the overlapping of cells in the image analysis for cancer
diagnosis, a new cell image analysis method is proposed based on watershed algorithm to separate the
clustering cells into single ones. Firstly, a distance map is produced to determine the number of seeds from
the clustering cells based on iterative erosion. Then, the ultra-erosion aggregates are taken as the seeds to
separate the cells. Finally, the images are grown from the seed regions until all of the image pixels except
the boundaries of convex have been assimilated. The design and implementation of the algorithm and
experimental results are presented.