Totally 2745 sweetpotato accessions were identified for resistance to black rot from 1984 to 2002. Results demonstrated that about 7.7% of varieties or lines were highly resistant, 17.7% resistant, 23.2% medium resistant, 27.2% susceptible and 24.3% highly susceptible. The analyses of the resistance of 898 lines showed that resistant plants could be obtained from the progeny of any parental combinations. However, the higher parental resistance was, the more percentage of resistant plants in their progeny was. Results of correlation analysis indicated that there was not any correlation between resistance to black rot of varieties and its main economic characters. A lot of improved varieties of resistance to black rot with high yield and good qualities have been developed.