A high quality BAC library of the oilseed Brassica juncea variety Sichuan Yellow Seed was constructed to accelerate the study and utilization of the yellowseed rapeseed genome.The library contains 82 944 clones and is stored in 216×384 microtiter plates.The results of restriction enzyme digestion of plasmid showed that the average insert size of the library was about 140 kb and the emptyvector rate was about 2.5%.Based on the Brassica juncea genome size of 1 000 Mb,the library covers about 11.6× genomes.The results of Blast analysis of the BAC end sequences showed that the clones were evenly mapped onto the 18 chromosomes of the Brassica juncea genome.No chloroplast,mitochondria and bacterium genome DNA contamination was found.