Identification of compatible parental line is of great importance in introduction of useful characters to onion breeding program, beyond the severe hybridization barrier. Phylogenic analysis of Allium section Cepa was conducted through PCR by URPs, repeated sequences of A. fistulosum, and microsatellite markers. Totally 76 accessions originated from 21 countries were clustered into five groups at a 0.84-similarity level: group I;A. cepa and its wild relatives and A. cepa ssp. ascalonicum, group II; A. cepa ssp. wakegii, A. cepa ssp. proliferum and Samcheung-pa group III; A. fistulosum and A. altaicum, group IV; A. galanthum, group V; Soeckkori-pa. Samcheung-pa and Soekkori-pa, Korean local varieties, shared band type of both Cepa group and Altaicum group, indicating that those are derived from interspecific hybridization between A. fistulosum and A. cepa.