Abstract: The RAPD was used to study the genetic diversity of 19 KinXin series potato cultivars. The result showed that 52 RAPD bands were amplified using 7 primer, among them 43 bands were polymorphic, and 4~9 bands were amplified in each lane. The RAPD analysis indicated that the genetic distance of 19 potato cultivars was between 0.17~0.72, average value was 0.39. When all of the polymorphic bands were analysed by cluster analysis, 19 potato cultivars were classified into 3 groups. The analysis showed that there existed close sibship among the majority of potato cultivars, and the genetic distance between the minority cultivars and the others is longer, which indicate that the genetic basis of KeXin series potato cultivars is wide. The RAPD is more suitable in the diversity study of potato cultivars, and suitable to analyse the sibship of potato cultivars in breeding.