Heredity groups were classified by cluster analysis with RAPD technology based on 20 rice varieties of hyogo prefecture of Japan. 11 primers, A 02 , A 08 , B 18 , C 15 , D 03 , D 08 , G 05 , M 11 , Q 16 , S 13 and T 06 , selected from 220 candidate primers act as polymorphic DNA (RAPD) makers for 20 rice. The maps of RAPD standard polymorphic DNA in different varieties can be established by their specific characteristic bands. Thus, the cultivars and their purity could be identified and analysed quickly. In addition, Genetic distance among 20 rice varieties was calculated and clustered with RAPD makers. The results showed that 20 rice varieties could be classified into four groups. The four groups classified by cluster analysis with RAPD technology is consistent with the expected grouping based on available pedigree. The current study indicated that it was practical to group rice with RAPD technology.