Abstract: In this study， we used chemical mutation breeding method to breed a new variety of purple sweet potato. We adopted 0， 0.5%， 1.0%， 1.5% of sodiumazide to treat with embryogenic cell masses for 6 hours by using parental Australian purple sweet potato of Au1990sp. The result showed that the treatment of 0.5% sodiumazide for 6 h was the best. After redifferentiation， the embryogenic callus in the treatment of 0.5% sodiumazide for 6 h were differentiated into 125 strains， and 99 strains were obtained after transplantation in 2003. Among the 14 strains selected in 2003， 3 strains obtained high yield， indicating 43.98 t·hm-2 of CA06， 40.03 t·hm-2 of CA11 and 43.84 t·hm-2 of CA17. The yield of the control group of Au1990sp was only 4.95 t·hm-2. Moreover， the mutated strains showed quite a lot of difference in phenotype， characteristics and features from parental strains. There were obvious differences between the parental strain of Au1990sp and the mutated strain by AFLP analysis. This new variety was named Yongzishu No.1 after 12 years breeding， which was approved to be a new non\|crop variety in December in 2012 in Zhejiang Province.

Key words: Yongzishu No. 1, mutation breeding, variety characteristic