One hundred and seventy seven accessions of hulled oat (Avena sativa L.) with domestic and oversea origins were analyzed using 20 AFLP primer combinations. Selective amplification created 976 unambiguous bands, of which 185 bands were polymorphic. The percentage of polymorphic bands for each AFLP primer combination ranged from 9.3% to 35.9%, with the average of 19.0%. Shannon-Weaver indices of groups of accessions with diverse geographic origins varied from 0.1900 to 0.3412. Western Europe group showed the highest index, followed by North Europe (0.3269), Japan (0.3072), Eastern Europe (0.2949) and North American group (0.2904), and Heilongjiang group showed the lowest. The results of PCA and UPGMA clustering analysis exhibited a good consistency, and were also consistent with geographic origins. All the accessions were classified into two categories based by PCAand UPGMA clustering analysis. One category covered mainly domestic accessions, the other category included accessions of Inner Mongolia and Qinghai as well as accessions from overseas. The exotic accessions were generally separated from domestic accessions while domestic accessions with different origins mixed up. This indicates that the relationship between domestic and oversea accessions was relatively far caused by lacking of effective exchange, and the domestic accessions of hulled oat were more homologous due to lack of diversity. It is important to promote the germplasm exchange with other countries and enrich the genetic diversity of hulled oat in China.