It is very important for rapeseed hybrid production to develop and utilize a novel cytoplasmic male sterility (CMS) system concerning the possible risk because of a narrow cytoplasm background.Here the anatomy of anther development in the CMS system, named NCa, was observed using light microscope and transmission electron microscope, and the restriction fragment length polymorphism (RFLP) analyses of mitochondrial DNA of NCa sterile line were also performed in comparison with the other rapeseed sterile lines, such as pol, nap, ogura, and tour.The anther abortion of this CMS line occurred at the later uninucleate microspore stage, and the anatomic aborting characteristics were obviously different from all the other rapeseed CMS lines reported before.The RFLP analyses revealed that five probe/enzyme combinations could distinguish the five CMS lines.The results of anatomic observations and mitochondrial DNA polymorphism indicated that the NCa CMS system is a novel one which differs from the pol, nap, ogura, and tour systems.