Abstract: Brassica is the vital research focus of comparative genomics in dicotyledons, and great progresses have been made in Brassica comparative genomics over the past 15 years. Extensive macrosynteny and microsynteny have been found not only within Brassica but also between Brassica and Arabidopsis thaliana, which suggests the feasibility of transferring the information from Arabidopsis to Brassica. In addition, several copies of conserved syntenic regions exist in Brassica, which supports the hypothesis that of the Brassica diploid species are evolved from a hexaploid ancestor.